Loans and Allowance for Loan Losses - Summary of Aging of Loans (Detail) - USD ($) $ in Thousands	Mar. 31, 2020		Dec. 31, 2019
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	$ 71,695		$ 60,413
Current	1,087,711		1,076,281
Total	1,159,406	[1]	1,136,694	[2]
Accruing	0		0
30-59 [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	41,861		40,779
60-89 [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	22,820		10,971
91+ [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	7,014		8,663
Recreation [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	40,116		41,583
Current	671,107		648,227
Total	711,223	[1]	689,810	[2]
Accruing	0		0
Recreation [Member] | 30-59 [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	28,231		27,357
Recreation [Member] | 60-89 [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	6,660		8,426
Recreation [Member] | 91+ [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	5,225		5,800
Home Improvement [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,296		1,542
Current	258,136		249,288
Total	259,432	[1]	250,830	[2]
Accruing	0		0
Home Improvement [Member] | 30-59 [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	912		931
Home Improvement [Member] | 60-89 [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	164		427
Home Improvement [Member] | 91+ [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	220		184
Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	107		107
Current	68,150		69,660
Total	68,257	[1]	69,767	[2]
Accruing	0		0
Commercial Loans [Member] | 91+ [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	107		107
Medallion [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	30,176		17,181
Current	90,318		109,106
Total	120,494	[1]	126,287	[2]
Accruing	0		0
Medallion [Member] | 30-59 [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	12,718		12,491
Medallion [Member] | 60-89 [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	15,996		2,118
Medallion [Member] | 91+ [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	$ 1,462		$ 2,572

[1] Excludes loan premiums of $5,429 resulting from purchase price accounting and $18,944 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.