Finance Receivables - Schedule of Financing Receivable Credit Quality Indicators (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Financing Receivable, Allowance for Credit Losses
Total	$ 1,870,648	$ 8,200,299	$ 1,870,648	$ 8,200,299	$ 7,689,477
Gross charge-offs
Total	49,256	65,029	188,737	207,109
Retail
Financing Receivable, Allowance for Credit Losses
Year 1	272,185	2,186,907	272,185	2,186,907	2,448,913
Year 2	226,281	1,966,753	226,281	1,966,753	1,780,330
Year 3	123,324	1,469,774	123,324	1,469,774	1,313,909
Year 4	50,014	803,189	50,014	803,189	702,736
Year 5	26,541	325,628	26,541	325,628	273,313
More than 5 years	5,949	209,724	5,949	209,724	161,905
Total	704,294	6,961,975	704,294	6,961,975	6,681,106
Gross charge-offs
Year 1			2,897	4,767	18,563
Year 2			48,622	67,005	93,963
Year 3			54,146	68,921	91,421
Year 4			41,996	36,981	48,433
Year 5			21,747	15,599	20,019
More than 5 years			13,987	13,836	17,607
Total	44,555	65,029	183,395	207,109	290,006
Retail | UNITED STATES
Financing Receivable, Allowance for Credit Losses
Year 1		2,140,696		2,140,696	2,402,090
Year 2		1,920,574		1,920,574	1,741,316
Year 3		1,439,402		1,439,402	1,288,745
Year 4		787,314		787,314	689,938
Year 5		317,872		317,872	267,460
More than 5 years		205,507		205,507	159,001
Total		6,811,365		6,811,365	6,548,550
Gross charge-offs
Year 1			2,771	4,680	18,322
Year 2			47,626	65,972	92,489
Year 3			53,155	67,945	90,023
Year 4			41,175	36,365	47,678
Year 5			21,364	15,270	19,628
More than 5 years			13,560	13,485	17,143
Total			179,651	203,717	285,283
Retail | CANADA
Financing Receivable, Allowance for Credit Losses
Year 1		46,211		46,211	46,823
Year 2		46,179		46,179	39,014
Year 3		30,372		30,372	25,164
Year 4		15,875		15,875	12,798
Year 5		7,756		7,756	5,853
More than 5 years		4,217		4,217	2,904
Total		150,610		150,610	132,556
Gross charge-offs
Year 1			126	87	241
Year 2			996	1,033	1,474
Year 3			991	976	1,398
Year 4			821	616	755
Year 5			383	329	391
More than 5 years			427	351	464
Total			3,744	3,392	4,723
Retail | Super prime | UNITED STATES
Financing Receivable, Allowance for Credit Losses
Year 1	144,780	931,374	144,780	931,374	1,040,491
Year 2	120,456	769,173	120,456	769,173	694,941
Year 3	61,502	507,694	61,502	507,694	449,697
Year 4	19,838	241,713	19,838	241,713	206,974
Year 5	12,198	84,111	12,198	84,111	67,668
More than 5 years	2,011	39,590	2,011	39,590	28,606
Total	360,785	2,573,655	360,785	2,573,655	2,488,377
Retail | Super prime | CANADA
Financing Receivable, Allowance for Credit Losses
Year 1		35,280		35,280	36,011
Year 2		34,382		34,382	29,098
Year 3		21,186		21,186	17,468
Year 4		10,573		10,573	8,330
Year 5		4,410		4,410	3,179
More than 5 years		1,702		1,702	1,096
Total		107,533		107,533	95,182
Retail | Prime | UNITED STATES
Financing Receivable, Allowance for Credit Losses
Year 1	125,804	927,821	125,804	927,821	1,042,910
Year 2	104,939	901,954	104,939	901,954	821,719
Year 3	60,992	730,870	60,992	730,870	659,000
Year 4	29,368	410,721	29,368	410,721	363,507
Year 5	13,633	166,169	13,633	166,169	141,495
More than 5 years	2,767	106,766	2,767	106,766	82,771
Total	337,503	3,244,301	337,503	3,244,301	3,111,402
Retail | Prime | CANADA
Financing Receivable, Allowance for Credit Losses
Year 1		9,200		9,200	9,111
Year 2		10,340		10,340	8,687
Year 3		8,054		8,054	6,724
Year 4		4,812		4,812	4,033
Year 5		2,782		2,782	2,212
More than 5 years		2,124		2,124	1,524
Total		37,312		37,312	32,291
Retail | Sub-prime | UNITED STATES
Financing Receivable, Allowance for Credit Losses
Year 1	1,601	281,501	1,601	281,501	318,689
Year 2	886	249,447	886	249,447	224,656
Year 3	830	200,838	830	200,838	180,048
Year 4	808	134,880	808	134,880	119,457
Year 5	710	67,592	710	67,592	58,297
More than 5 years	1,171	59,151	1,171	59,151	47,624
Total	$ 6,006	993,409	$ 6,006	993,409	948,771
Retail | Sub-prime | CANADA
Financing Receivable, Allowance for Credit Losses
Year 1		1,731		1,731	1,701
Year 2		1,457		1,457	1,229
Year 3		1,132		1,132	972
Year 4		490		490	435
Year 5		564		564	462
More than 5 years		391		391	284
Total		$ 5,765		$ 5,765	$ 5,083