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			6 Months Ended
	Jun. 30, 2020		Jun. 30, 2019	Jun. 30, 2020		Jun. 30, 2019
Loans and Leases Receivable Disclosure [Line Items]
Loans collateral in process of foreclosure - beginning balance	$ 46,817		$ 49,808	$ 52,711	[1]	$ 49,495
Transfer from loans, net	5,188		10,354	12,125		19,451
Sales	(1,988)		(2,209)	(4,286)		(4,662)
Cash payments received	(185)		(1,931)	(1,893)		(4,505)
Collateral valuation adjustments	(2,457)		(3,654)	(11,282)		(7,411)
Loans collateral in process of foreclosure - ending balance	47,375	[1]	52,368	47,375	[1]	52,368
Recreation [Member]
Loans and Leases Receivable Disclosure [Line Items]
Loans collateral in process of foreclosure - beginning balance	1,717		1,180	1,476		1,503
Transfer from loans, net	3,003		3,491	7,781		6,883
Sales	(1,988)		(2,034)	(3,986)		(4,111)
Collateral valuation adjustments	(1,474)		(1,682)	(4,013)		(3,320)
Loans collateral in process of foreclosure - ending balance	1,258		955	1,258		955
Medallion [Member]
Loans and Leases Receivable Disclosure [Line Items]
Loans collateral in process of foreclosure - beginning balance	45,100		48,628	51,235		47,992
Transfer from loans, net	2,185		6,863	4,344		12,568
Sales			(175)	(300)		(551)
Cash payments received	(185)		(1,931)	(1,893)		(4,505)
Collateral valuation adjustments	(983)		(1,972)	(7,269)		(4,091)
Loans collateral in process of foreclosure - ending balance	$ 46,117		$ 51,413	$ 46,117		$ 51,413

[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 $9,265 as of June 30, 2020 and $8,163 as of December 31, 2019.