Loans and Allowance for Loan Losses - Summary of Aging of Loans (Detail) - USD ($) $ in Thousands		Sep. 30, 2020		Dec. 31, 2019
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		$ 109,076		$ 60,413
Current		1,146,139		1,076,281
Total		1,255,215	[1]	1,136,694	[2]
Accruing		0		0
30-59 [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		25,011		40,779
60-89 [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		70,662		10,971
91+ [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		13,403		8,663
Recreation [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		26,236		41,583
Current		750,857		648,227
Total		777,093	[1]	689,810	[2]
Accruing		0		0
Recreation [Member] | 30-59 [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		16,070		27,357
Recreation [Member] | 60-89 [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		6,092		8,426
Recreation [Member] | 91+ [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		4,074		5,800
Home Improvement [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		1,116		1,542
Current		317,476		249,288
Total		318,592	[1]	250,830	[2]
Accruing		0		0
Home Improvement [Member] | 30-59 [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		733		931
Home Improvement [Member] | 60-89 [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		281		427
Home Improvement [Member] | 91+ [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		102		184
Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		1,902		107
Current		69,467		69,660
Total		71,369	[1]	69,767	[2]
Accruing		0		0
Commercial Loans [Member] | 91+ [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		1,902		107
Medallion [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		79,822		17,181
Current		8,332		109,106
Total		88,154	[1]	126,287	[2]
Accruing		0		0
Medallion [Member] | 30-59 [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		8,208		12,491
Medallion [Member] | 60-89 [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		64,289		2,118
Medallion [Member] | 91+ [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		7,325		$ 2,572
Strategic Partnership [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current		7
Total	[1]	7
Accruing		$ 0

[1] Excludes loan premiums of $4,358 resulting from purchase price accounting and $21,481 of capitalized loan origination costs.

[2] Excludes loan premiums of $5,758 resulting from purchase price accounting and $18,403 of capitalized loan origination costs.