Series A Preferred Stock [Member] Class of Stock [Axis] Series B Preferred Stock [Member] Direct Mail Revenues [Member] Income Statement Location [Axis] Convenience Fee Revenue [Member] Recoveries on previously charged-off contracts [Member] Sales Tax Refunds [Member] Other Income [Member] Residual interest financing [Member] Long-term Debt, Type [Axis] Subordinated renewable notes [Member] Warehouse lines of credit [Member] CreditFacility [Axis] Warehouse lines of credit (2) [Member] CPS 2011-B [Member] MajorTypesOfDebtAndEquitySecurities [Axis] CPS 2011-C [Member] CPS 2012-A [Member] CPS 2012-B [Member] CPS 2012-C [Member] CPS 2012-D [Member] CPS 2013-A [Member] CPS 2013-B [Member] CPS 2013-C [Member] CPS 2013-D [Member] CPS 2014-A [Member] CPS 2014-B [Member] CPS 2014-C [Member] CPS 2014-D [Member] CPS 2015-A [Member] CPS 2015-B [Member] CPS 2015-C [Member] CPS 2016-A [Member] Warehouse lines of credit (3) [Member] Securitization Trust Debt [Member] Warehouse lines of credit [Member] Level 1 [Member] FairValueByFairValueHierarchyLevel [Axis] Level 2 [Member] Level 3 [Member] Carrying Value [Member] Financial Instrument [Axis] Financing Receivables, 30 to 59 Days Past Due [Member] Financing Receivables, Period Past Due [Axis] Financing Receivables, 60 to 89 Days Past Due [Member] Financing Receivables, Equal to Greater than 90 Days Past Due [Member] CPS 2016-B [Member] Document And Entity Information Entity Registrant Name Entity Central Index Key Document Type Document Period End Date Amendment Flag Current Fiscal Year End Date Is Entity a Well-known Seasoned Issuer? Is Entity a Voluntary Filer? Is Entity's Reporting Status Current? Entity Filer Category Entity Public Float Entity Common Stock, Shares Outstanding Document Fiscal Period Focus Document Fiscal Year Focus Statement [Table] Statement [Line Items] ASSETS Cash and cash equivalents Restricted cash and equivalents Finance receivables Less: Allowance for finance credit losses Finance receivables, net Finance receivables measured at fair value Furniture and equipment, net Deferred tax assets, net Accrued interest receivable Other assets Total LIABILITIES AND SHAREHOLDERS' EQUITY Liabilities Accounts payable and accrued expenses Warehouse lines of credit Residual interest financing Securitization trust debt Subordinated renewable notes Total COMMITMENTS AND CONTINGENCIES Shareholders' Equity Preferred stock, $1 par value; authorized Common stock, no par value; authorized 75,000,000 shares; 24,088,674 and 25,616,460 shares issued and outstanding at June 30, 2016 and December 31, 2015, respectively Retained earnings Accumulated other comprehensive loss Total stockholders' equity Total liabilities and stockholders' equity Preferred Stock, Par Value Preferred Stock, Authorized Preferred Stock, Issued Preferred Stock, Outstanding Common Stock, No Par Value Common Stock, Authorized Common Stock, Issued Common Stock, Outstanding Income Statement [Abstract] Revenues: Interest income Servicing fees Other income Total revenues Expenses: Employee costs General and administrative Interest Provision for credit losses Marketing Occupancy Depreciation and amortization Total operating expenses Income before income tax expense Income tax expense Net income Earnings per share: Basic Diluted Number of shares used in computing earnings per share: Basic Diluted Statement of Comprehensive Income [Abstract] Net income Other comprehensive income/(loss); change in funded status of pension plan Comprehensive income Statement of Cash Flows [Abstract] Cash flows from operating activities: Adjustments to reconcile net income to net cash provided by operating activities: Accretion of deferred acquisition fees Amortization of discount on securitization trust debt Depreciation and amortization Amortization of deferred financing costs Stock-based compensation expense Interest income on residual assets Changes in assets and liabilities: Accrued interest receivable Deferred tax assets, net Other assets Accounts payable and accrued expenses Net cash provided by operating activities Cash flows from investing activities: Purchases of finance receivables held for investment Payments received on finance receivables held for investment Payments received on receivables portfolio at fair value Change in repossessions held in inventory Increases in restricted cash and cash equivalents, net Purchase of furniture and equipment Net cash used in investing activities Cash flows from financing activities: Proceeds from issuance of securitization trust debt Proceeds from issuance of subordinated renewable notes Payments on subordinated renewable notes Net repayments of warehouse lines of credit Repayments of residual interest financing debt Repayment of securitization trust debt Repayment of debt secured by receivables measured at fair value Payment of financing costs Purchase of common stock Exercise of options and warrants Net cash provided by financing activities Increase (decrease) in cash and cash equivalents Cash and cash equivalents at beginning of period Cash and cash equivalents at end of period Supplemental disclosure of cash flow information: Cash paid during the period for: Interest Income taxes Accounting Policies [Abstract] Summary of Significant Accounting Policies Finance Receivables Finance Receivables Securitization Trust Debt Securitization Trust Debt Debt Disclosure [Abstract] Debt Interest Income And Interest Expense Interest Income and Interest Expense Earnings Per Share [Abstract] Earnings Per Share Income Tax Disclosure [Abstract] Income Taxes Legal Proceedings Legal Proceedings Employee Benefits Employee Benefits Fair Value Disclosures [Abstract] Fair Value Measurements Description of Business Basis of Presentation Use of Estimates Other Income Warrants Stock-based Compensation Purchases of Company Stock New Accounting Pronouncements Reclassifications Financial Covenants Provision for Contingent Liabilities Other Income Stock option activity Financial Receivables Delinquency status of finance receivables Allowance for credit losses Allowance for losses on repossessed inventory Securitization trust debt Debt Outstanding Interest Income And Interest Expense Tables Interest income Interest expense Computation of basic and diluted earnings per share Net periodic cost (benefit) Estimated fair values of financial assets and liabilities Primary components of Other Income Other income for the period Number of Shares Outstanding options, beginning balance Granted Exercised Forfeited Outstanding options, ending balance Options exercisable Weighted Average Exercise Price Outstanding options, beginning balance Granted Exercised Forfeited Outstanding options, ending balance Options exercisable Weighted Average Remaining Contractual Term Weighted Average Remaining Contractual Term, beginning Weighted Average Remaining Contractual Term, ending Options exercisable Warrants outstanding Stock based compensation costs Unrecognized stock-based compensation costs Unrecognized stock-based compensation costs amortization period Aggregate intrinsic value outstanding Aggregate intrinsic value exercisable Options Exercised Total intrinsic value of options exercised Shares available for future grants Repurchase of common stock, shares repurchased Repurchase of common stock average share price Finance Receivables Automobile finance receivables, net of unearned interest Less: Unearned acquisition fees and originations costs Finance Receivables Delinquency Status Current Finance receivables Balance at beginning of period Provision for credit losses on finance receivables Charge-offs Recoveries Balance at end of period Gross balance of repossessions in inventory Allowance for losses on repossessed inventory Net repossessed inventory included in other assets Finance receivables Schedule of Held-to-maturity Securities [Table] Schedule of Held-to-maturity Securities [Line Items] Major Types of Debt and Equity Securities [Axis] "Securitization trust debt," and components of debt Final Scheduled Payment Date Receivables Pledged at end of period Initial Principal Outstanding Principal Weighted Average Contractual Interest Rate Restricted Cash for securitization trust debt Pre-funding proceeds Expected finance receivable payments 2016 Expected finance receivable payments 2017 Expected finance receivable payments 2018 Expected finance receivable payments 2019 Expected finance receivable payments 2020 Expected finance receivable payments 2021 Debt issuance costs Fair Value, Option, Qualitative Disclosures Related to Election [Table] Fair Value, Option, Qualitative Disclosures Related to Election [Line Items] Credit Facility [Axis] Debt issuance costs Total other debt outstanding Interest rate Maturity date Interest Income Details Components of interest income Interest on Finance Receivables Residual interest income Other interest income Interest income Total interest expense Weighted average common shares - basic Incremental common shares attibutable to exercise of outstanding options and warrants Weighted average common shares - diluted Antidilutive common stock equivalents Unrecognized tax benefits Deferred tax asset U.S. federal deferred tax assets State deferred tax assets Net operating loss carryforward Effective income tax rate Litigation accrual Components of net periodic cost (benefit) Service cost Interest cost Expected return on assets Amortization of transition (asset)/obligation Amortization of net (gain)/loss Net periodic cost (benefit) Plan contribution Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Hierarchy [Axis] Assets: Cash and cash equivalents Finance receivables, net Finance receivables measured at fair value Liabilities: Warehouse lines of credit Accrued interest payable Residual interest financing Securitization trust debt Subordinated renewable notes Fair Value Measurements Details Narrative Finance receivables related to reposessed vehicles in inventory Valuation adjustment, loss allowance Recovery rate Estimated fair value and carrying amount of repossed inventory Accretion of deferred acquisition fees Allowance for losses on repossessed inventory table text block CPS2011B Member. CPS2011C Member. CPS2012A Member. CPS2012B Member. CPS 2012 C member Custom Element. CPS 2013 A Member CPS 2013 B Member CPS 2013 C Member CPS 2013 D Member CPS 2014 A Member CPS 2014 B Member CPS 2014 C Member CPS 2014 D Member CPS 2015 A Member CPS 2015 B Member Cash paid (received) during the period for: abstract Change in repossessions in inventory Convenience Fee Member Direct Mail Revenues Member Number of Shares [Abstract] Other income policy text block Other income table text block Payments on receivables portfolio at fair value Provision for Contingent Liabilities policy text block Purchases of Company Stock policy text block Purchases of finance receivables held for investment Recoveries Member Repurchase of common stock average share price Residual Interest Financing Member. Residual Interest Income. Pre-funding proceeds on securitization trust debt Sales Tax Refunds Member Securitization Trust Debt Initial Principal Weighted Average Remaining Contractual Term, beginning Subordinated Renewable Notes. Warehouse Lines Of Credit 1 Member Warehouse Lines Of Credit 2 Member Weighted Average Exercise Price [Abstract] Weighted Average Remaining Contractual Term [Abstract] Warrants policy text block CPS 2015C Member Final Scheduled Payment Date CPS 2016 A Member Expected finance receivable payments year one Expected finance receivable payments year two Expected finance receivable payments year three Expected finance receivable payments year four Expected finance receivable payments year five Expected finance receivable payments year six Warehouse Lines Of Credit 3 Member Securitization Trust Debt Member Warehouse Lines Of Credit Member Total Amount Member Finance receivables, net at fair value Recovery rate WarehouseLinesOfCreditMember Financing Receivable, Allowance for Credit Losses Notes, Loans and Financing Receivable, Net, Current Assets Liabilities [Default Label] Stockholders' Equity Attributable to Parent Liabilities and Equity Revenues Direct Operating Costs Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest Depreciation, Depletion and Amortization Interest Income, Other Increase (Decrease) in Accrued Interest Receivable, Net Increase (Decrease) in Prepaid Expense and Other Assets Increase (Decrease) in Other Operating Assets Increase (Decrease) in Accounts Payable and Accrued Liabilities Net Cash Provided by (Used in) Operating Activities, Continuing Operations PurchasesOfFinanceReceivablesHeldForInvestment Payments for (Proceeds from) Loans Receivable ChangeInRepossessionsInInventory Increase (Decrease) in Restricted Cash for Operating Activities Payments to Acquire Property, Plant, and Equipment Net Cash Provided by (Used in) Investing Activities, Continuing Operations Repayments of Long-term Debt, Long-term Capital Lease Obligations, and Capital Securities Repayments of Lines of Credit Repayments of Other Debt Repayments of Secured Debt Repayments of Subordinated Short-term Debt Payments of Financing Costs Payments for Repurchase of Common Stock Net Cash Provided by (Used in) Financing Activities, Continuing Operations Cash and Cash Equivalents, Period Increase (Decrease) Interest Paid, Net Finance, Loan and Lease Receivables, Held-for-investment, Policy [Policy Text Block] Long-term Debt [Text Block] Legal Matters and Contingencies [Text Block] Compensation and Employee Benefit Plans [Text Block] OtherIncomeTableTextBlock Schedule of Maturities of Long-term Debt [Table Text Block] Interest and Other Income [Table Text Block] Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term Proceeds from Sale and Collection of Finance Receivables [Abstract] Loans and Leases Receivable, Allowance Financing Receivable, Recorded Investment, Past Due Allowance for Doubtful Accounts Receivable, Write-offs Financing Receivable, Recorded Investment, Nonaccrual Status Debt Issuance Costs, Line of Credit Arrangements, Gross Other Long-term Debt Defined Benefit Plan, Net Periodic Benefit Cost Cash and Cash Equivalents, Fair Value Disclosure Securities Borrowed, Fair Value Disclosure Lines of Credit, Fair Value Disclosure Other Liabilities, Fair Value Disclosure Financial Liabilities Fair Value Disclosure Loans Payable, Fair Value Disclosure TotalAmountMember