Loans and Allowance for Credit Losses - Summary of Activity in Allowance for Credit Losses (Parenthetical) (Detail) - USD ($)		3 Months Ended			9 Months Ended
		Sep. 30, 2023		Sep. 30, 2022	Sep. 30, 2023		Sep. 30, 2022	Jun. 30, 2023	Dec. 31, 2022	[1]	Jun. 30, 2022	Dec. 31, 2021
Financing Receivable, Allowance for Credit Losses [Line Items]
Cumulative charges of loans and loan collateral process of foreclosure		$ 15,923,000	[1]	$ 24,331,000	$ 15,923,000	[1]	$ 24,331,000	$ 16,803,000	$ 21,819,000		$ 26,974,000	$ 37,430,000
Net charge-offs	[2]	10,370,000		$ 7,664,000	25,469,000		9,677,000
Strategic Partnership [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Net charge-offs					0		$ 0
Medallion Bank [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Cumulative charges of loans and loan collateral process of foreclosure		$ 201,700,000			$ 201,700,000

[1] Includes financed sales of this collateral to third parties that are reported separately from the loan portfolio, of $6.2 million as of September 30, 2023 and $7.5 million as of December 31, 2022.

[2] As of September 30, 2023, cumulative net charge-offs of loans and loan collateral in process of foreclosure in the taxi medallion loan portfolio were $201.7 million, some of which may represent collection opportunities for the Company.