Loans and Allowance for Loan Losses - Summary of Activities of the Loan Collateral in Process of Foreclosure Related to Recreation and Medallion Loans (Detail) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2020		Sep. 30, 2019	Sep. 30, 2020		Sep. 30, 2019
Loans and Leases Receivable Disclosure [Line Items]
Loans collateral in process of foreclosure - beginning balance	$ 47,375		$ 52,368	$ 52,711	[1]	$ 49,495
Transfer from loans, net	13,444		6,434	25,569		25,884
Sales	(1,697)		(1,991)	(5,984)		(6,614)
Cash payments received	(426)		(1,556)	(2,318)		(6,100)
Collateral valuation adjustments	(9,954)		(1,716)	(21,236)		(9,126)
Loans collateral in process of foreclosure - ending balance	48,742	[1]	53,539	48,742	[1]	53,539
Recreation [Member]
Loans and Leases Receivable Disclosure [Line Items]
Loans collateral in process of foreclosure - beginning balance	1,258		955	1,476		1,503
Transfer from loans, net	2,833		3,429	10,615		10,311
Sales	(1,697)		(1,604)	(5,684)		(5,715)
Collateral valuation adjustments	(1,395)		(1,603)	(5,408)		(4,922)
Loans collateral in process of foreclosure - ending balance	999		1,177	999		1,177
Medallion [Member]
Loans and Leases Receivable Disclosure [Line Items]
Loans collateral in process of foreclosure - beginning balance	46,117		51,413	51,235		47,992
Transfer from loans, net	10,611		3,005	14,954		15,573
Sales			(387)	(300)		(899)
Cash payments received	(426)		(1,556)	(2,318)		(6,100)
Collateral valuation adjustments	(8,559)		(113)	(15,828)		(4,204)
Loans collateral in process of foreclosure - ending balance	$ 47,743		$ 52,362	$ 47,743		$ 52,362

[1] Includes financed sales of this collateral to third parties that are reported separately from the loan portfolio, and that are conducted by the Bank of $9,701 as of September 30, 2020 and $8,163 as of December 31, 2019.