Loans and Allowance for Loan Losses - Summary of Aging of Loans (Detail) - USD ($) $ in Thousands	Mar. 31, 2019		Dec. 31, 2018
Financing Receivable, Recorded Investment, Past Due [Line Items]
31-60	$ 76,890		$ 58,085
Current	923,625		935,703
Total	1,000,515	[1]	993,788	[2]
Accruing	0		0
Recreation [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
31-60	20,487		28,158
Current	569,065		539,051
Total	589,552	[1]	567,209	[2]
Accruing	0		0
Home Improvement [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
31-60	775		1,133
Current	195,120		184,528
Total	195,895	[1]	185,661	[2]
Accruing	0		0
Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
31-60	710		733
Current	54,501		63,350
Total	55,211	[1]	64,083	[2]
Accruing	0		0
Medallion [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
31-60	54,918		28,061
Current	104,939		148,774
Total	159,857	[1]	176,835	[2]
Accruing	0		0
31-60 [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
31-60	61,277		27,887
31-60 [Member] | Recreation [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
31-60	13,186		18,483
31-60 [Member] | Home Improvement [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
31-60	436		715
31-60 [Member] | Medallion [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
31-60	47,655		8,689
61-90 [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
31-60	7,511		10,044
61-90 [Member] | Recreation [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
31-60	4,019		5,655
61-90 [Member] | Home Improvement [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
31-60	183		283
61-90 [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
31-60			454
61-90 [Member] | Medallion [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
31-60	3,309		3,652
91+ [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
31-60	8,102		20,154
91+ [Member] | Recreation [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
31-60	3,282		4,020
91+ [Member] | Home Improvement [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
31-60	156		135
91+ [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
31-60	710		279
91+ [Member] | Medallion [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
31-60	$ 3,954		$ 15,720

[1] Excludes loan premiums of $7,956 resulting from purchase price accounting and $15,729 of capitalized loan origination costs.

[2] Excludes loan premiums of $9,047 resulting from purchase price accounting and $15,047 of capitalized loan origination costs.