Loans and Allowance for Loan Losses - Summary of Allowance for Loan Losses by Type (Detail) - USD ($) $ in Thousands		Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment, Past Due [Line Items]
Amount	[1]	$ 46,093	$ 36,395
Percentage of Allowance		100.00%	100.00%
Allowance as a Percent of Loan Category		3.97%	3.58%
Recreation [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Amount		$ 18,075	$ 6,856
Percentage of Allowance		39.00%	19.00%
Allowance as a Percent of Loan Category		2.53%	1.17%
Home Improvement [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Amount		$ 2,608	$ 1,796
Percentage of Allowance		6.00%	5.00%
Allowance as a Percent of Loan Category		1.05%	0.98%
Medallion [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Amount		$ 25,410	$ 27,743
Percentage of Allowance		55.00%	76.00%
Allowance as a Percent of Loan Category		19.48%	15.11%

[1] Includes $3,173 of a general reserve as of December 31, 2019, for the Company, for current and performing medallion loans under 90 days past due, as an additional buffer against future losses, representing 7% of the total allowance, and 2.56% of the loans in question. 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 general reserves benefit of $2,230.