Loans and Allowance for Loan Losses - Schedule of Activity of Gross Loans (Detail) - USD ($)		12 Months Ended
		Dec. 31, 2020		Dec. 31, 2019		Dec. 31, 2018
Schedule Of Gross Real Estate And Loan Activity [Line Items]
Gross loans, beginning balance	[1]	$ 1,136,694,000
Charge-offs, net	[2]	(58,362,000)		$ (37,688,000)
Transfer to loan collateral in process of foreclosure, net		(47,274,000)		(31,348,000)
Amortization of origination costs		(6,022,000)		(4,952,000)		$ (3,132,000)	[3]
Paid-in-kind interest		1,188,000		834,000		1,869,000	[3]
Loans transferred to other foreclosed property		1,800,000
Gross loans, ending balance		1,205,776,000	[4]	1,136,694,000	[1]
Recreation [Member]
Schedule Of Gross Real Estate And Loan Activity [Line Items]
Gross loans, beginning balance	[1]	689,810,000
Transfer to loan collateral in process of foreclosure, net		(14,871,000)		(14,512,000)
Gross loans, ending balance		767,374,000	[4]	689,810,000	[1]
Home Improvement [Member]
Schedule Of Gross Real Estate And Loan Activity [Line Items]
Gross loans, beginning balance	[1]	250,830,000
Gross loans, ending balance		336,885,000	[4]	250,830,000	[1]
Medallion [Member]
Schedule Of Gross Real Estate And Loan Activity [Line Items]
Gross loans, beginning balance	[1]	126,287,000
Transfer to loan collateral in process of foreclosure, net		(32,403,000)		(16,836,000)
Gross loans, ending balance		36,153,000	[4]	126,287,000	[1]
Strategic Partnership [Member]
Schedule Of Gross Real Estate And Loan Activity [Line Items]
Charge-offs, net		0
Gross loans, ending balance	[4]	24,000
Bank Holding Company Accounting [Member]
Schedule Of Gross Real Estate And Loan Activity [Line Items]
Gross loans, beginning balance		1,160,855,000		1,017,882,000
Loan originations		497,221,000		462,093,000
Principal payments, sales, and maturities		(321,831,000)		(251,653,000)
Charge-offs, net		(58,362,000)		(37,688,000)
Transfer to loan collateral in process of foreclosure, net		(47,254,000)		(31,348,000)
Amortization of origination costs		(6,022,000)		(4,952,000)
Amortization of loan premium		(3,042,000)		(3,289,000)
FASB origination costs, net		8,885,000		8,976,000
Paid-in-kind interest		1,188,000		834,000
Loans transferred to other foreclosed property		(1,800,000)
Gross loans, ending balance		1,229,838,000		1,160,855,000		1,017,882,000
Bank Holding Company Accounting [Member] | Recreation [Member]
Schedule Of Gross Real Estate And Loan Activity [Line Items]
Gross loans, beginning balance		713,332,000		587,038,000
Loan originations		294,885,000		301,403,000
Principal payments, sales, and maturities		(187,989,000)		(146,873,000)
Charge-offs, net		(14,457,000)		(17,419,000)
Transfer to loan collateral in process of foreclosure, net		(14,871,000)		(14,512,000)
Amortization of origination costs		(7,809,000)		(6,428,000)
Amortization of loan premium		(191,000)		(247,000)
FASB origination costs, net		9,786,000		10,370,000
Gross loans, ending balance		792,686,000		713,332,000		587,038,000
Bank Holding Company Accounting [Member] | Home Improvement [Member]
Schedule Of Gross Real Estate And Loan Activity [Line Items]
Gross loans, beginning balance		247,324,000		183,155,000
Loan originations		193,098,000		142,112,000
Principal payments, sales, and maturities		(105,813,000)		(76,157,000)
Charge-offs, net		(1,229,000)		(786,000)
Amortization of origination costs		1,910,000		1,561,000
Amortization of loan premium		(320,000)		(416,000)
FASB origination costs, net		(937,000)		(2,145,000)
Gross loans, ending balance		334,033,000		247,324,000		183,155,000
Bank Holding Company Accounting [Member] | Commercial [Member]
Schedule Of Gross Real Estate And Loan Activity [Line Items]
Gross loans, beginning balance		69,767,000		64,083,000
Loan originations		7,575,000		18,578,000
Principal payments, sales, and maturities		(13,183,000)		(13,553,000)
Charge-offs, net		(28,000)		(819,000)
Amortization of origination costs		8,000		34,000
FASB origination costs, net				610,000
Paid-in-kind interest		1,188,000		834,000
Gross loans, ending balance		65,327,000		69,767,000		64,083,000
Bank Holding Company Accounting [Member] | Medallion [Member]
Schedule Of Gross Real Estate And Loan Activity [Line Items]
Gross loans, beginning balance		130,432,000		183,606,000
Principal payments, sales, and maturities		(13,207,000)		(15,070,000)
Charge-offs, net		(42,648,000)		(18,664,000)
Transfer to loan collateral in process of foreclosure, net		(32,383,000)		(16,836,000)
Amortization of origination costs		(131,000)		(119,000)
Amortization of loan premium		(2,531,000)		(2,626,000)
FASB origination costs, net		36,000		141,000
Loans transferred to other foreclosed property		(1,800,000)
Gross loans, ending balance		37,768,000		$ 130,432,000		$ 183,606,000
Bank Holding Company Accounting [Member] | Strategic Partnership [Member]
Schedule Of Gross Real Estate And Loan Activity [Line Items]
Loan originations		1,663,000
Principal payments, sales, and maturities		(1,639,000)
Gross loans, ending balance		$ 24,000

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

[2] As of December 31, 2020, cumulative charge-offs of loans and loan collateral in process of foreclosure in the medallion loan portfolio were $279,188, some of which represents collection opportunities for the Company.

[3] Balance includes the nine months ended December 31, 2018 under Bank Holding Company Accounting and the three months ended March 31, 2018 under Investment Company Accounting.

[4] Excludes loan premiums of $2,717 resulting from purchase price accounting and $21,345 of capitalized loan origination costs.