Loans and Allowance for Loan Losses - Summary of Performance Status of Loan (Detail) $ in Thousands	Jun. 30, 2018 USD ($)
Financing Receivable, Recorded Investment [Line Items]
Status of loans	$ 1,150,123
Recreation [Member]
Financing Receivable, Recorded Investment [Line Items]
Status of loans	597,348
Home Improvement [Member]
Financing Receivable, Recorded Investment [Line Items]
Status of loans	195,876
Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Status of loans	80,105
Medallion [Member]
Financing Receivable, Recorded Investment [Line Items]
Status of loans	276,794
Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Status of loans	1,100,565
Performing [Member] | Recreation [Member]
Financing Receivable, Recorded Investment [Line Items]
Status of loans	593,177
Performing [Member] | Home Improvement [Member]
Financing Receivable, Recorded Investment [Line Items]
Status of loans	195,759
Performing [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Status of loans	72,664
Performing [Member] | Medallion [Member]
Financing Receivable, Recorded Investment [Line Items]
Status of loans	238,965
Non - Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Status of loans	49,558
Non - Performing [Member] | Recreation [Member]
Financing Receivable, Recorded Investment [Line Items]
Status of loans	4,171
Non - Performing [Member] | Home Improvement [Member]
Financing Receivable, Recorded Investment [Line Items]
Status of loans	117
Non - Performing [Member] | Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Status of loans	7,441
Non - Performing [Member] | Medallion [Member]
Financing Receivable, Recorded Investment [Line Items]
Status of loans	$ 37,829