Loans and Allowance for Credit Losses - Summary of Activity in Allowance for Loan Losses (Detail) - USD ($) $ in Thousands	3 Months Ended						6 Months Ended
	Jun. 30, 2025		Mar. 31, 2025		Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2025		Jun. 30, 2024
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses - beginning balance	$ 100,366		$ 97,368	[1]	$ 83,827	$ 84,235	$ 97,368	[1]	$ 84,235
Charge-offs	(21,224)		(24,646)		(18,690)	(22,999)
Total recoveries	6,192		5,630		6,074	5,390
Provision (benefit) for credit losses	21,562		22,014		18,577	17,201	43,576		35,778
Allowance for credit losses - ending balance	106,896	[2]	100,366		89,788	83,827	106,896	[2]	89,788
Recreation [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses - beginning balance	71,558		71,102		60,009	57,532	71,102		57,532
Charge-offs	(16,273)		(20,274)		(14,627)	(18,101)
Total recoveries	4,419		3,860		3,962	3,548
Provision (benefit) for credit losses	15,336		16,870		15,795	17,030
Allowance for credit losses - ending balance	75,040		71,558		65,139	60,009	75,040		65,139
Home Improvement [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses - beginning balance	20,249		20,536		17,930	21,019	20,536		21,019
Charge-offs	(4,951)		(4,227)		(4,063)	(4,898)
Total recoveries	1,190		1,095		1,243	911
Provision (benefit) for credit losses	3,934		2,845		3,279	898
Allowance for credit losses - ending balance	20,422		20,249		18,389	17,930	20,422		18,389
Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses - beginning balance	8,174		5,190		4,384	4,148	5,190		4,148
Charge-offs	0		(130)		0	0
Total recoveries	10		0		0	20
Provision (benefit) for credit losses	2,912		3,114		478	216
Allowance for credit losses - ending balance	11,096		8,174		4,862	4,384	11,096		4,862
Taxi Medallion [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for credit losses - beginning balance	385	[3]	540	[3]	1,504	1,536	540	[3]	1,536
Charge-offs	0	[3]	(15)	[3]	0	0
Total recoveries	573	[3]	675	[3]	869	911
Provision (benefit) for credit losses	(620)	[3]	(815)	[3]	(975)	(943)
Allowance for credit losses - ending balance	$ 338	[3]	$ 385	[3]	$ 1,398	$ 1,504	$ 338	[3]	$ 1,398

[1] As of December 31, 2024, total allowance for credit losses as a percent of nonaccrual loans was 291.93%

[2] As of June 30, 2025, total allowance for credit losses as a percent of nonaccrual loans was 288.09%.

[3] As of June 30, 2025, cumulative net charge-offs of loans and loan collateral in process of foreclosure in the taxi medallion portfolio were $161.5 million, including $95.2 million related to loans secured by New York taxi medallions, some of which may represent collection opportunities for the Company.