Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	3 Months Ended			9 Months Ended		12 Months Ended
	Sep. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021	Apr. 02, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Interest-bearing funds deposited in other banks	$ 1,300,000			$ 1,300,000
Non-marketable securities	10,700,000			10,700,000		$ 9,700,000
Impact of equity investment	2,000,000.0			2,000,000.0
Past Due	42,860,000			42,860,000		41,761,000
Notes receivable net	79,500			79,500
Investment securities Amortized to interest income	100,000		$ 100,000	100,000	$ 100,000
Net loan origination costs				34,300,000		26,100,000
Net amortization to income	(2,300,000)		(2,000,000.0)	$ (6,800,000)	(5,800,000)
Percentage of write down of loan balance				40.00%
Principal portion of loans serviced, fair value	19,600,000			$ 19,600,000		20,500,000
Loans write down to collateral value	13,171,000		3,978,000	$ 27,139,000	27,075,000
Intangible assets useful life				20 years
Goodwill	150,803,000			$ 150,803,000		150,803,000
Intangible assets, net	22,398,000			22,398,000		23,480,000
Amortization of intangible assets	359,000		362,000	1,082,000	1,083,000
Financing receivable, recorded investment, 90 days past due and still accruing	0			0		0
Depreciation and amortization	100,000		100,000	300,000	200,000
Amortization expense	700,000		600,000	2,000,000.0	$ 1,800,000
Deferred costs	7,200,000			$ 7,200,000		$ 7,100,000
Potential dilutive common shares excluded from EPS computation				657,579	26,000
Stock based compensation award				0	317,398
Stock based compensation award, Amount	$ 1,000,000.0		$ 600,000	$ 2,500,000	$ 1,700,000
Stock based compensation award per diluted common share	$ 0.04		$ 0.02	$ 0.10	$ 0.07
Unrecognized compensation cost related to unvested stock options and restricted stock	$ 4,100,000			$ 4,100,000
Unrecognized compensation cost related to unvested stock options and restricted stock, recognition period				10 months
Tier 1 leverage capital to total assets ratio	15.00%			15.00%
Tier 1 leverage capital ratio	16.20%			16.20%
Capital conversation buffer				2.50%		2.50%
Restricted Shares [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stock based compensation award		383,925		383,925	163,561	258,120
Restricted Stock Units [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stock based compensation award				129,638	16,803
RPAC [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Past Due							$ 12,400,000
Financing receivable, recorded investment, 90 days past due and still accruing	$ 100,000			$ 100,000		$ 500,000
Loan portfolio premium amortized to interest income	200,000		$ 200,000	500,000	$ 2,000,000.0
Medallion Bank [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Amortization of intangible assets				0		0
New York City [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans write down to collateral value				79,500
91+ [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Past Due	5,968,000			5,968,000		4,024,000
91+ [Member] | Loans [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Past Due	$ 6,000,000.0			$ 6,000,000.0		$ 4,000,000.0
Total loans more than 90 days past due ,percentage	0.33%			0.33%		0.28%
Bank Holding Company Accounting [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net premium on investment securities				$ 100,000		$ 300,000
Other Assets [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Equity securities, fair value	$ 1,700,000			$ 1,700,000		$ 2,000,000.0
Equity Securities [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Purchased of equity securities with readily determinable fair value					$ 2,000,000.0
Minimum [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Interest bearing loan term				4 years
Estimated useful life of fixed assets				3 years
Maximum [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Interest bearing loan term				7 years
Estimated useful life of fixed assets				10 years