Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)		3 Months Ended		12 Months Ended
	Jan. 01, 2023	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023	Dec. 31, 2021
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Interest-bearing funds deposited in other banks		$ 1,300,000
Non-marketable securities		16,400,000		$ 11,400,000
Impact of equity investment		4,000,000
Cumulative Appreciation		4,700,000
Past Due		70,517,000		81,013,000
Notes receivable net		79,500
Purchased of equity securities with readily determinable fair value					$ 2,000,000
Investment, Type [Extensible Enumeration]					Equity Securities [Member]
Equity securities, fair value		1,700,000		1,700,000
Net loan origination costs		40,700,000		40,000,000
Net Amortization to income		2,000,000	$ 1,900,000
Amount of loan charged off			2,500,000
Principal portion of loans serviced, fair value		14,000,000		14,000,000
Loans write down to collateral value		$ 22,999,000	18,097,000
Intangible assets useful life		20 years
Goodwill		$ 150,803,000		150,803,000
Intangible assets, net		20,230,000		20,591,000
Amortization of intangible assets		361,000	360,000
Depreciation and amortization		100,000	100,000
Amortization expense		800,000	$ 800,000
Deferred costs		$ 8,500,000		$ 8,500,000
Potential dilutive common shares excluded from EPS computation		9,000	9,000
Stock based compensation award, Amount		$ 1,500,000	$ 1,000,000
Stock based compensation award per diluted common share		$ 0.06	$ 0.05
Unrecognized compensation cost related to unvested stock options and restricted stock		$ 9,300,000
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		16.40%
Capital conversation buffer		2.50%		2.50%
Consumer Loan [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase in allowance for credit losses on loans	$ 13,700,000
Commercial Loans [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing receivable allowance for credit loss	$ 9,900,000
Restricted Shares [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stock based compensation award		296,178	304,749	399,793
Restricted Stock Units [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stock based compensation award		0	0
Performance Shares [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stock based compensation award		215,687		296,444
Stock based compensation award		215,687	0
Medallion Bank [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Amortization of intangible assets				$ 0
90+ [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Past Due		$ 16,132,000		16,837,000
90+ [Member] | Loans [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Past Due		$ 16,100,000		$ 16,800,000
Total loans more than 90 days past due ,percentage		0.74%		0.77%
Bank Holding Company Accounting [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net premium on investment securities		$ 100,000		$ 100,000
Minimum [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Interest bearing loan term		5 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		6 years
Investment securities Amortized to interest income		$ 100,000	$ 100,000
Estimated useful life of fixed assets		10 years