(5) Securitization Trust Debt (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Receivables Pledged at end of period	[1]	$ 1,972,684
Initial Principal		5,945,962
Outstanding Principal		1,814,320	$ 2,109,766
Expected finance receivable payments 2021		818,400
Expected finance receivable payments 2022		450,900
Expected finance receivable payments 2023		350,700
Expected finance receivable payments 2024		81,100
Expected finance receivable payments 2025		83,700
Expected finance receivable payments 2026		$ 18,700
CPS 2014-C [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Final Scheduled Payment Date	[2]	December 2021
Receivables Pledged at end of period	[1]	$ 0
Initial Principal		273,000
Outstanding Principal		$ 0	19,758
Weighted Average Contractual Interest Rate		0.00%
CPS 2014-D [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Final Scheduled Payment Date	[2]	March 2022
Receivables Pledged at end of period	[1]	$ 0
Initial Principal		267,500
Outstanding Principal		$ 0	23,755
Weighted Average Contractual Interest Rate		0.00%
CPS 2015-A [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Final Scheduled Payment Date	[2]	June 2022
Receivables Pledged at end of period	[1]	$ 0
Initial Principal		245,000
Outstanding Principal		$ 0	26,713
Weighted Average Contractual Interest Rate		0.00%
CPS 2015-B [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Final Scheduled Payment Date	[2]	September 2022
Receivables Pledged at end of period	[1]	$ 17,737
Initial Principal		250,000
Outstanding Principal		$ 17,984	36,338
Weighted Average Contractual Interest Rate		6.01%
CPS 2015-C [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Final Scheduled Payment Date	[2]	December 2022
Receivables Pledged at end of period	[1]	$ 27,788
Initial Principal		300,000
Outstanding Principal		$ 28,529	53,579
Weighted Average Contractual Interest Rate		6.77%
CPS 2016-A [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Final Scheduled Payment Date	[2]	March 2023
Receivables Pledged at end of period	[1]	$ 35,042
Initial Principal		329,460
Outstanding Principal		$ 37,158	71,599
Weighted Average Contractual Interest Rate		7.24%
CPS 2016-B [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Final Scheduled Payment Date	[2]	June 2023
Receivables Pledged at end of period	[1]	$ 45,407
Initial Principal		332,690
Outstanding Principal		$ 46,079	82,667
Weighted Average Contractual Interest Rate		7.42%
CPS 2016-C [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Final Scheduled Payment Date	[2]	September 2023
Receivables Pledged at end of period	[1]	$ 47,358
Initial Principal		318,500
Outstanding Principal		$ 47,325	83,696
Weighted Average Contractual Interest Rate		7.53%
CPS 2016-D [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Final Scheduled Payment Date	[2]	April 2024
Receivables Pledged at end of period	[1]	$ 38,498
Initial Principal		206,325
Outstanding Principal		$ 36,455	65,021
Weighted Average Contractual Interest Rate		5.81%
CPS 2017-A [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Final Scheduled Payment Date	[2]	April 2024
Receivables Pledged at end of period	[1]	$ 42,972
Initial Principal		206,320
Outstanding Principal		$ 40,619	71,450
Weighted Average Contractual Interest Rate		5.82%
CPS 2017-B [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Final Scheduled Payment Date	[2]	December 2023
Receivables Pledged at end of period	[1]	$ 53,753
Initial Principal		225,170
Outstanding Principal		$ 39,016	76,201
Weighted Average Contractual Interest Rate		5.00%
CPS 2017-C [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Final Scheduled Payment Date	[2]	September 2024
Receivables Pledged at end of period	[1]	$ 56,048
Initial Principal		224,825
Outstanding Principal		$ 47,553	80,315
Weighted Average Contractual Interest Rate		4.82%
CPS 2017-D [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Final Scheduled Payment Date	[2]	June 2024
Receivables Pledged at end of period	[1]	$ 57,986
Initial Principal		196,300
Outstanding Principal		$ 49,297	83,801
Weighted Average Contractual Interest Rate		4.32%
CPS 2018-A [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Final Scheduled Payment Date	[2]	March 2025
Receivables Pledged at end of period	[1]	$ 62,902
Initial Principal		190,000
Outstanding Principal		$ 53,549	91,258
Weighted Average Contractual Interest Rate		4.11%
CPS 2018-B [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Final Scheduled Payment Date	[2]	December 2024
Receivables Pledged at end of period	[1]	$ 75,400
Initial Principal		201,823
Outstanding Principal		$ 66,955	111,188
Weighted Average Contractual Interest Rate		4.51%
CPS 2018-C [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Final Scheduled Payment Date	[2]	September 2025
Receivables Pledged at end of period	[1]	$ 87,223
Initial Principal		230,275
Outstanding Principal		$ 77,345	130,064
Weighted Average Contractual Interest Rate		4.62%
CPS 2018-D [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Final Scheduled Payment Date	[2]	June 2025
Receivables Pledged at end of period	[1]	$ 104,155
Initial Principal		233,730
Outstanding Principal		$ 88,228	149,470
Weighted Average Contractual Interest Rate		4.58%
CPS 2019-A [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Final Scheduled Payment Date	[2]	March 2026
Receivables Pledged at end of period	[1]	$ 131,575
Initial Principal		254,400
Outstanding Principal		$ 114,373	186,900
Weighted Average Contractual Interest Rate		4.38%
CPS 2019-B [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Final Scheduled Payment Date	[2]	June 2026
Receivables Pledged at end of period	[1]	$ 128,787
Initial Principal		228,275
Outstanding Principal		$ 118,982	184,308
Weighted Average Contractual Interest Rate		3.95%
CPS 2019-C [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Final Scheduled Payment Date	[2]	September 2026
Receivables Pledged at end of period	[1]	$ 150,637
Initial Principal		243,513
Outstanding Principal		$ 142,080	216,650
Weighted Average Contractual Interest Rate		3.26%
CPS 2019-D [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Final Scheduled Payment Date	[2]	December 2026
Receivables Pledged at end of period	[1]	$ 190,916
Initial Principal		274,313
Outstanding Principal		$ 181,485	265,035
Weighted Average Contractual Interest Rate		2.80%
CPS 2020-A [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Final Scheduled Payment Date	[2]	March 2027
Receivables Pledged at end of period	[1]	$ 187,537
Initial Principal		260,000
Outstanding Principal		$ 184,944	0
Weighted Average Contractual Interest Rate		2.80%
CPS 2020-B [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Final Scheduled Payment Date	[2]	June 2027
Receivables Pledged at end of period	[1]	$ 187,597
Initial Principal		202,343
Outstanding Principal		$ 164,403	0
Weighted Average Contractual Interest Rate		3.09%
CPS 2020-C [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Final Scheduled Payment Date	[2]	November  2027
Receivables Pledged at end of period	[1]	$ 243,367
Initial Principal		252,200
Outstanding Principal		$ 231,961	$ 0
Weighted Average Contractual Interest Rate		1.67%

[1] Includes repossessed assets that are included in Other Assets on our Consolidated Balance Sheets.

[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 $818.4 million in 2021, $450.9 million in 2022, $350.7 million in 2023, $81.1 million in 2024, $83.7 million in 2025, and $18.7 million in 2026.