Loans and Allowance for Loan Losses - Schedule of Activity of Gross Loans (Detail) - USD ($)		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Schedule Of Gross Real Estate And Loan Activity [Line Items]
Gross loans, beginning balance	[1]			$ 1,136,694,000
Charge-offs, net	[2]	$ (16,216,000)	$ (5,894,000)	(28,814,000)	$ (30,133,000)
Transfer to loan collateral in process of foreclosure, net		(13,444,000)	(6,434,000)	(25,569,000)	(25,884,000)
Amortization of origination costs				(4,572,000)	(3,753,000)
Paid-in-kind interest				940,000	637,000
Transfer to other foreclosed property				(1,800,000)
Gross loans, ending balance	[3]	1,255,215,000		1,255,215,000
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		(2,833,000)	(3,429,000)	(10,615,000)	(10,311,000)
Gross loans, ending balance	[3]	777,093,000		777,093,000
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	[3]	318,592,000		318,592,000
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		(10,611,000)	(3,005,000)	(14,954,000)	(15,573,000)
Gross loans, ending balance	[3]	88,154,000		88,154,000
Strategic Partnership [Member]
Schedule Of Gross Real Estate And Loan Activity [Line Items]
Charge-offs, net		0	0	0	0
Gross loans, ending balance	[3]	7,000		7,000
Bank Holding Company Accounting [Member]
Schedule Of Gross Real Estate And Loan Activity [Line Items]
Gross loans, beginning balance		1,260,594,000	1,088,475,000	1,160,855,000	1,017,882,000
Loan originations		137,091,000	130,053,000	396,446,000	366,330,000
Principal payments, sales and maturities		(85,335,000)	(64,552,000)	(222,612,000)	(187,168,000)
Charge-offs, net		(16,216,000)	(5,894,000)	(28,814,000)	(30,133,000)
Transfer to loan collateral in process of foreclosure, net		(13,423,000)	(6,434,000)	(25,549,000)	(25,884,000)
Amortization of origination costs		(1,681,000)	(1,364,000)	(4,572,000)	(3,753,000)
Amortization of loan premium		(893,000)	(713,000)	(1,401,000)	(2,886,000)
FASB origination costs		2,411,000	2,499,000	7,561,000	7,257,000
Paid-in-kind interest		306,000	212,000	940,000	637,000
Transfer to other foreclosed property		(1,800,000)		(1,800,000)
Gross loans, ending balance		1,281,054,000	1,142,282,000	1,281,054,000	1,142,282,000
Bank Holding Company Accounting [Member] | Recreation [Member]
Schedule Of Gross Real Estate And Loan Activity [Line Items]
Gross loans, beginning balance		786,785,000	668,540,000	713,332,000	587,038,000
Loan originations		73,534,000	82,662,000	249,383,000	248,989,000
Principal payments, sales and maturities		(54,161,000)	(39,068,000)	(140,688,000)	(112,208,000)
Charge-offs, net		(850,000)	(3,489,000)	(10,796,000)	(10,853,000)
Transfer to loan collateral in process of foreclosure, net		(2,833,000)	(3,429,000)	(10,615,000)	(10,311,000)
Amortization of origination costs		(2,093,000)	(1,723,000)	(5,853,000)	(4,743,000)
Amortization of loan premium		(49,000)	(59,000)	(152,000)	(195,000)
FASB origination costs		2,605,000	2,959,000	8,327,000	8,676,000
Gross loans, ending balance		802,938,000	706,393,000	802,938,000	706,393,000
Bank Holding Company Accounting [Member] | Home Improvement [Member]
Schedule Of Gross Real Estate And Loan Activity [Line Items]
Gross loans, beginning balance		282,072,000	209,549,000	247,324,000	183,155,000
Loan originations		62,515,000	42,641,000	140,693,000	102,821,000
Principal payments, sales and maturities		(29,312,000)	(21,096,000)	(72,034,000)	(54,168,000)
Charge-offs, net		(65,000)	(51,000)	(897,000)	(295,000)
Amortization of origination costs		509,000	367,000	1,406,000	1,060,000
Amortization of loan premium		(81,000)	(107,000)	(248,000)	(327,000)
FASB origination costs		(196,000)	(577,000)	(802,000)	(1,520,000)
Gross loans, ending balance		315,442,000	230,726,000	315,442,000	230,726,000
Bank Holding Company Accounting [Member] | Commercial [Member]
Schedule Of Gross Real Estate And Loan Activity [Line Items]
Gross loans, beginning balance		71,476,000	64,442,000	69,767,000	64,083,000
Loan originations		900,000	4,750,000	6,075,000	14,520,000
Principal payments, sales and maturities		(1,318,000)	(375,000)	(5,422,000)	(10,180,000)
Charge-offs, net		3,000	(819,000)	3,000	(819,000)
Amortization of origination costs		2,000	2,000	6,000	32,000
FASB origination costs			(3,000)		(64,000)
Paid-in-kind interest		306,000	212,000	940,000	637,000
Gross loans, ending balance		71,369,000	68,209,000	71,369,000	68,209,000
Bank Holding Company Accounting [Member] | Medallion [Member]
Schedule Of Gross Real Estate And Loan Activity [Line Items]
Gross loans, beginning balance		120,253,000	145,944,000	130,432,000	183,606,000
Principal payments, sales and maturities		(401,000)	(4,013,000)	(4,180,000)	(10,612,000)
Charge-offs, net		(15,304,000)	(1,535,000)	(17,124,000)	(18,166,000)
Transfer to loan collateral in process of foreclosure, net		(10,590,000)	(3,005,000)	(14,934,000)	(15,573,000)
Amortization of origination costs		(99,000)	(10,000)	(131,000)	(102,000)
Amortization of loan premium		(763,000)	(547,000)	(1,001,000)	(2,364,000)
FASB origination costs		2,000	120,000	36,000	165,000
Transfer to other foreclosed property		(1,800,000)		(1,800,000)
Gross loans, ending balance		91,298,000	$ 136,954,000	91,298,000	$ 136,954,000
Bank Holding Company Accounting [Member] | Strategic Partnership [Member]
Schedule Of Gross Real Estate And Loan Activity [Line Items]
Gross loans, beginning balance		8,000
Loan originations		142,000		295,000
Principal payments, sales and maturities		(143,000)		(288,000)
Gross loans, ending balance		$ 7,000		$ 7,000

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

[2] As of September 30, 2020, cumulative net charge-offs of loans and loan collateral in process of foreclosure in the medallion loan portfolio were $268,745, representing collection opportunities for the Company.

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