Loans and Allowance for Loan Losses - Summary of Activity in Allowance for Loan Losses (Detail) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses - beginning balance		$ 46,093	$ 36,395
Total charge-offs		(11,179)	(15,862)
Total recoveries		2,602	2,986
Net charge-offs	[1]	(8,577)	(12,876)
Provision for loan losses		16,541	13,343
Allowance for loan losses – ending balance	[2]	54,057	36,862
Recreation [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses - beginning balance		18,075
Total charge-offs		(8,244)	(6,525)
Total recoveries		1,862	1,596
Allowance for loan losses – ending balance		22,294
Home Improvement [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses - beginning balance		2,608
Total charge-offs		(1,011)	(549)
Total recoveries		375	390
Allowance for loan losses – ending balance		3,507
Medallion [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses - beginning balance		25,410
Total charge-offs		(1,924)	(8,788)
Total recoveries		365	$ 1,000
Allowance for loan losses – ending balance		$ 28,256

[1] As of March 31, 2020, cumulative net charge-offs of loans and loan collateral in process of foreclosure in the medallion loan portfolio were $243,428, representing collection opportunities for the Company.

[2] Includes $2,469 of a general reserve for the Company, for current and performing medallion loans under 90 days past due, as an additional buffer against future losses, representing 5% of the total allowance, and 2.07% of the medallion loans under 90 days past due as of March 31, 2020. This figure excludes $17,351 of a general reserve on loans at the Bank, which was netted against loan balances at consolidation on April 2, 2018. Subsequent to April 2, 2018, the Bank recorded a general reserve benefit of $7,266.