(3) Securitization Trust Debt (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2022	Dec. 31, 2023	Dec. 31, 2021
Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Line Items]
Receivables Pledged at end of period	[1]	$ 2,003,373
Initial Principal		4,851,034
Outstanding Principal		1,826,016		$ 1,771,953
Securitization Trust Debt, payable in 2022		556,300
Securitization Trust Debt, payable in 2023		703,800
Securitization Trust Debt, payable in 2024		178,000
Securitization Trust Debt, payable in 2025		197,300
Securitization Trust Debt, payable in 2026		114,100
Securitization Trust Debt, payable in 2027		58,400
Securitization Trust Debt, payable in 2028		$ 5,500
CPS 2017-A [Member]
Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Line Items]
Final Scheduled Payment Date	[2]	April 2024
Receivables Pledged at end of period	[1]	$ 0
Initial Principal		206,320
Outstanding Principal		$ 0		17,644
Weighted Average Contractual Interest Rate		0.00%
CPS 2017-B [Member]
Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Line Items]
Final Scheduled Payment Date	[2]	December 2023
Receivables Pledged at end of period	[1]	$ 22,739
Initial Principal		225,170
Outstanding Principal		$ 7,491		12,491
Weighted Average Contractual Interest Rate		5.75%
CPS 2017-C [Member]
Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Line Items]
Final Scheduled Payment Date	[2]	September 2024
Receivables Pledged at end of period	[1]	$ 24,874
Initial Principal		224,825
Outstanding Principal		$ 20,955	$ 25,846
Weighted Average Contractual Interest Rate		5.72%
CPS 2017-D [Member]
Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Line Items]
Final Scheduled Payment Date	[2]	June 2024
Receivables Pledged at end of period	[1]	$ 25,965
Initial Principal		196,300
Outstanding Principal		$ 22,589		26,744
Weighted Average Contractual Interest Rate		5.17%
CPS 2018-A [Member]
Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Line Items]
Final Scheduled Payment Date	[2]	March 2025
Receivables Pledged at end of period	[1]	$ 29,215
Initial Principal		190,000
Outstanding Principal		$ 25,303		29,518
Weighted Average Contractual Interest Rate		4.86%
CPS 2018-B [Member]
Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Line Items]
Final Scheduled Payment Date	[2]	December 2024
Receivables Pledged at end of period	[1]	$ 35,386
Initial Principal		201,823
Outstanding Principal		$ 30,749		36,092
Weighted Average Contractual Interest Rate		5.24%
CPS 2018-C [Member]
Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Line Items]
Final Scheduled Payment Date	[2]	September 2025
Receivables Pledged at end of period	[1]	$ 40,840
Initial Principal		230,275
Outstanding Principal		$ 36,876		42,765
Weighted Average Contractual Interest Rate		5.41%
CPS 2018-D [Member]
Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Line Items]
Final Scheduled Payment Date	[2]	June 2025
Receivables Pledged at end of period	[1]	$ 50,069
Initial Principal		233,730
Outstanding Principal		$ 42,922		49,634
Weighted Average Contractual Interest Rate		5.24%
CPS 2019-A [Member]
Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Line Items]
Final Scheduled Payment Date	[2]	March 2026
Receivables Pledged at end of period	[1]	$ 62,139
Initial Principal		254,400
Outstanding Principal		$ 53,492		62,667
Weighted Average Contractual Interest Rate		5.05%
CPS 2019-B [Member]
Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Line Items]
Final Scheduled Payment Date	[2]	June 2026
Receivables Pledged at end of period	[1]	$ 62,243
Initial Principal		228,275
Outstanding Principal		$ 53,392		61,730
Weighted Average Contractual Interest Rate		4.77%
CPS 2019-C [Member]
Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Line Items]
Final Scheduled Payment Date	[2]	September 2026
Receivables Pledged at end of period	[1]	$ 73,278
Initial Principal		243,513
Outstanding Principal		$ 64,980		75,065
Weighted Average Contractual Interest Rate		3.91%
CPS 2019-D [Member]
Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Line Items]
Final Scheduled Payment Date	[2]	December 2026
Receivables Pledged at end of period	[1]	$ 94,335
Initial Principal		274,313
Outstanding Principal		$ 83,924		98,625
Weighted Average Contractual Interest Rate		3.32%
CPS 2020-A [Member]
Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Line Items]
Final Scheduled Payment Date	[2]	March 2027
Receivables Pledged at end of period	[1]	$ 88,745
Initial Principal		260,000
Outstanding Principal		$ 83,987		99,485
Weighted Average Contractual Interest Rate		3.48%
CPS 2020-B [Member]
Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Line Items]
Final Scheduled Payment Date	[2]	June 2027
Receivables Pledged at end of period	[1]	$ 96,567
Initial Principal		202,343
Outstanding Principal		$ 72,955		87,048
Weighted Average Contractual Interest Rate		4.98%
CPS 2020-C [Member]
Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Line Items]
Final Scheduled Payment Date	[2]	November 2027
Receivables Pledged at end of period	[1]	$ 129,864
Initial Principal		252,200
Outstanding Principal		$ 118,901		138,899
Weighted Average Contractual Interest Rate		2.57%
CPS 2021-A [Member]
Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Line Items]
Final Scheduled Payment Date	[2]	March 2028
Receivables Pledged at end of period	[1]	$ 138,427
Initial Principal		230,545
Outstanding Principal		$ 123,688		147,516
Weighted Average Contractual Interest Rate		1.08%
CPS 2021-B
Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Line Items]
Final Scheduled Payment Date	[2]	June 2028
Receivables Pledged at end of period	[1]	$ 165,925
Initial Principal		240,000
Outstanding Principal		$ 157,719		179,856
Weighted Average Contractual Interest Rate		1.36%
CPS 2021 C [Member]
Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Line Items]
Final Scheduled Payment Date	[2]	September 2028
Receivables Pledged at end of period	[1]	$ 235,461
Initial Principal		291,000
Outstanding Principal		$ 222,432		250,003
Weighted Average Contractual Interest Rate		1.21%
C P S 2021 D [Member]
Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Line Items]
Final Scheduled Payment Date	[2]	December 2028
Receivables Pledged at end of period	[1]	$ 311,727
Initial Principal		349,202
Outstanding Principal		$ 300,177		330,325
Weighted Average Contractual Interest Rate		1.47%
CPS 2020 D [Member]
Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Line Items]
Final Scheduled Payment Date	[2]	April 2029
CPS 2022 A [Member]
Debt Securities, Held-to-Maturity, Allowance for Credit Loss [Line Items]
Receivables Pledged at end of period	[1]	$ 315,574
Initial Principal		316,800
Outstanding Principal		$ 303,481		$ 0
Weighted Average Contractual Interest Rate		1.85%

[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 $556.3 million in 2022, $703.8 million in 2023, $178.0 million in 2024, $197.3 million in 2025, $114.1 million in 2026, $58.4 million in 2027, and $5.5 million in 2028.