(3) Securitization Trust Debt (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2021	Dec. 31, 2020
SecuritizationTrustDebtLineItems [Line Items]
Receivables Pledged at end of period	[1]	$ 1,949,099
Initial Principal		5,391,007
Outstanding Principal		1,802,375	$ 1,814,320
Expected finance receivable payments 2021		642,900
Expected finance receivable payments 2022		498,500
Expected finance receivable payments 2023		411,900
Expected finance receivable payments 2024		100,400
Expected finance receivable payments 2025		102,200
Expected finance receivable payments 2026		33,700
Expected finance receivable payments 2027		$ 2,000
CPS 2015-B [Member]
SecuritizationTrustDebtLineItems [Line Items]
Final Scheduled Payment Date	[2]	September 2022
Receivables Pledged at end of period	[1]	$ 0
Initial Principal		250,000
Outstanding Principal		$ 0	17,984
Weighted Average Contractual Interest Rate		0.00%
CPS 2015-C [Member]
SecuritizationTrustDebtLineItems [Line Items]
Final Scheduled Payment Date	[2]	December 2022
Receivables Pledged at end of period	[1]	$ 21,749
Initial Principal		300,000
Outstanding Principal		$ 23,929	28,529
Weighted Average Contractual Interest Rate		6.87%
CPS 2016-A [Member]
SecuritizationTrustDebtLineItems [Line Items]
Final Scheduled Payment Date	[2]	March 2023
Receivables Pledged at end of period	[1]	$ 28,459
Initial Principal		329,460
Outstanding Principal		$ 30,958	37,158
Weighted Average Contractual Interest Rate		7.65%
CPS 2016-B [Member]
SecuritizationTrustDebtLineItems [Line Items]
Final Scheduled Payment Date	[2]	June 2023
Receivables Pledged at end of period	[1]	$ 37,418
Initial Principal		332,690
Outstanding Principal		$ 38,724	46,079
Weighted Average Contractual Interest Rate		7.58%
CPS 2016-C [Member]
SecuritizationTrustDebtLineItems [Line Items]
Final Scheduled Payment Date	[2]	September 2023
Receivables Pledged at end of period	[1]	$ 39,455
Initial Principal		318,500
Outstanding Principal		$ 40,046	47,325
Weighted Average Contractual Interest Rate		7.82%
CPS 2016-D [Member]
SecuritizationTrustDebtLineItems [Line Items]
Final Scheduled Payment Date	[2]	April 2024
Receivables Pledged at end of period	[1]	$ 32,599
Initial Principal		206,325
Outstanding Principal		$ 30,753	36,455
Weighted Average Contractual Interest Rate		6.05%
CPS 2017-A [Member]
SecuritizationTrustDebtLineItems [Line Items]
Final Scheduled Payment Date	[2]	April 2024
Receivables Pledged at end of period	[1]	$ 36,408
Initial Principal		206,320
Outstanding Principal		$ 34,412	40,619
Weighted Average Contractual Interest Rate		6.04%
CPS 2017-B [Member]
SecuritizationTrustDebtLineItems [Line Items]
Final Scheduled Payment Date	[2]	December 2023
Receivables Pledged at end of period	[1]	$ 46,080
Initial Principal		225,170
Outstanding Principal		$ 31,951	39,016
Weighted Average Contractual Interest Rate		5.23%
CPS 2017-C [Member]
SecuritizationTrustDebtLineItems [Line Items]
Final Scheduled Payment Date	[2]	September 2024
Receivables Pledged at end of period	[1]	$ 48,489
Initial Principal		224,825
Outstanding Principal		$ 41,953	47,553
Weighted Average Contractual Interest Rate		4.95%
CPS 2017-D [Member]
SecuritizationTrustDebtLineItems [Line Items]
Final Scheduled Payment Date	[2]	June 2024
Receivables Pledged at end of period	[1]	$ 50,010
Initial Principal		196,300
Outstanding Principal		$ 43,273	49,297
Weighted Average Contractual Interest Rate		4.48%
CPS 2018-A [Member]
SecuritizationTrustDebtLineItems [Line Items]
Final Scheduled Payment Date	[2]	March 2025
Receivables Pledged at end of period	[1]	$ 54,744
Initial Principal		190,000
Outstanding Principal		$ 47,230	53,549
Weighted Average Contractual Interest Rate		4.25%
CPS 2018-B [Member]
SecuritizationTrustDebtLineItems [Line Items]
Final Scheduled Payment Date	[2]	December 2024
Receivables Pledged at end of period	[1]	$ 65,851
Initial Principal		201,823
Outstanding Principal		$ 58,112	66,955
Weighted Average Contractual Interest Rate		4.65%
CPS 2018-C [Member]
SecuritizationTrustDebtLineItems [Line Items]
Final Scheduled Payment Date	[2]	September 2025
Receivables Pledged at end of period	[1]	$ 76,364
Initial Principal		230,275
Outstanding Principal		$ 68,625	77,345
Weighted Average Contractual Interest Rate		4.74%
CPS 2018-D [Member]
SecuritizationTrustDebtLineItems [Line Items]
Final Scheduled Payment Date	[2]	June 2025
Receivables Pledged at end of period	[1]	$ 91,484
Initial Principal		233,730
Outstanding Principal		$ 78,446	88,228
Weighted Average Contractual Interest Rate		4.68%
CPS 2019-A [Member]
SecuritizationTrustDebtLineItems [Line Items]
Final Scheduled Payment Date	[2]	March 2026
Receivables Pledged at end of period	[1]	$ 115,227
Initial Principal		254,400
Outstanding Principal		$ 99,017	114,373
Weighted Average Contractual Interest Rate		4.50%
CPS 2019-B [Member]
SecuritizationTrustDebtLineItems [Line Items]
Final Scheduled Payment Date	[2]	June 2026
Receivables Pledged at end of period	[1]	$ 113,420
Initial Principal		228,275
Outstanding Principal		$ 105,045	118,982
Weighted Average Contractual Interest Rate		4.06%
CPS 2019-C [Member]
SecuritizationTrustDebtLineItems [Line Items]
Final Scheduled Payment Date	[2]	September 2026
Receivables Pledged at end of period	[1]	$ 133,374
Initial Principal		243,513
Outstanding Principal		$ 125,430	142,080
Weighted Average Contractual Interest Rate		3.35%
CPS 2019-D [Member]
SecuritizationTrustDebtLineItems [Line Items]
Final Scheduled Payment Date	[2]	December 2026
Receivables Pledged at end of period	[1]	$ 168,358
Initial Principal		274,313
Outstanding Principal		$ 160,999	181,485
Weighted Average Contractual Interest Rate		2.88%
CPS 2020-A [Member]
SecuritizationTrustDebtLineItems [Line Items]
Final Scheduled Payment Date	[2]	March 2027
Receivables Pledged at end of period	[1]	$ 165,519
Initial Principal		260,000
Outstanding Principal		$ 163,649	184,944
Weighted Average Contractual Interest Rate		2.89%
CPS 2020-B [Member]
SecuritizationTrustDebtLineItems [Line Items]
Final Scheduled Payment Date	[2]	June 2027
Receivables Pledged at end of period	[1]	$ 168,416
Initial Principal		202,343
Outstanding Principal		$ 147,587	164,403
Weighted Average Contractual Interest Rate		3.31%
CPS 2020-C [Member]
SecuritizationTrustDebtLineItems [Line Items]
Final Scheduled Payment Date	[2]	November 2027
Receivables Pledged at end of period	[1]	$ 223,358
Initial Principal		252,200
Outstanding Principal		$ 214,018	231,961
Weighted Average Contractual Interest Rate		1.75%
CPS 2021-A [Member]
SecuritizationTrustDebtLineItems [Line Items]
Final Scheduled Payment Date	[2]	March 2028
Receivables Pledged at end of period	[1]	$ 232,317
Initial Principal		230,545
Outstanding Principal		$ 218,218	$ 0
Weighted Average Contractual Interest Rate		0.77%

[1] Includes repossessed assets that are included in Other assets on our Unaudited Condensed Consolidated Balance Sheet.

[2] The Final Scheduled Payment Date represents final legal maturity of the securitization trust debt. Securitization trust debt is expected to become due and to be paid prior to those dates, based on amortization of the finance receivables pledged to the trusts. Expected payments, which will depend on the performance of such receivables, as to which there can be no assurance, are $642.9 million in 2021, $498.5 million in 2022, $411.9 million in 2023, $100.4 million in 2024, $102.2 million in 2025, $33.7 million in 2026, and $2.0 million in 2027.