Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2022	Mar. 31, 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
Non-marketable securities	10,100,000		$ 9,700,000
Past Due	31,393,000		41,761,000
Notes receivable net	79,500
Investment securities Amortized to interest income	100,000	$ 100,000
Net loan origination costs	28,400,000		26,100,000
Net amortization to income	$ (2,100,000)	(1,700,000)
Percentage of write down of loan balance	40.00%
Principal portion of loans serviced, fair value	$ 20,500,000		20,500,000
Loans write down to collateral value	$ (7,786,000)	(6,848,000)
Intangible assets useful life	20 years
Goodwill	$ 150,803,000		150,803,000
Intangible assets, net	23,120,000		23,480,000
Amortization of intangible assets	360,000	361,000
Financing receivable, recorded investment, 90 days past due and still accruing	0		0
Depreciation and amortization	100,000	100,000
Amortization expense	600,000	$ 600,000
Deferred costs	$ 7,200,000		$ 7,100,000
Potential dilutive common shares excluded from EPS computation	466,867	1,188,455
Stock based compensation award	0	317,398
Stock based compensation award, Amount	$ 600,000	$ 500,000
Stock based compensation award per diluted common share	$ 0.02	$ 0.02
Unrecognized compensation cost related to unvested stock options and restricted stock	$ 5,100,000
Unrecognized compensation cost related to unvested stock options and restricted stock, recognition period	12 months
Tier 1 leverage capital to total assets ratio	15.00%
Tier 1 leverage capital ratio	17.51%
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	163,561	258,120
Restricted Stock Units [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stock based compensation award	0	0
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	$ 400,000		$ 500,000
Loan portfolio premium amortized to interest income	100,000	$ 100,000
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	4,173,000		4,024,000
91+ [Member] | Loans [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Past Due	$ 4,200,000		$ 4,000,000.0
Total loans more than 90 days past due ,percentage	0.27%		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	$ 1,900,000		$ 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