Funds Borrowed - Additional Information (Detail)						3 Months Ended		9 Months Ended		12 Months Ended
		Feb. 28, 2021 USD ($)	Jul. 31, 2020 USD ($)	Dec. 31, 2007 USD ($)	Jun. 30, 2007 USD ($) shares	Sep. 30, 2022 USD ($) shares	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($) Deposit shares	Sep. 30, 2021 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2021 USD ($) shares	Apr. 30, 2021 USD ($)	Mar. 15, 2021 USD ($)	Dec. 31, 2020 USD ($)	Aug. 31, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2017 USD ($)
Debt Instrument [Line Items]
Number of individual with time deposits greater than $100,000 | Deposit								0
Listing services deposits from other financial institutions.						$ 9,200,000		$ 9,200,000			$ 8,700,000
Maturity date		Feb. 28, 2026	Sep. 24, 2024
Debt instrument face amount			$ 25,000,000.0
Issue of common stock | shares						28,529,993		28,529,993			28,124,629
Preferred securities repurchased from a third party investor				$ 2,000,000.0
Long-term debt	[1]					$ 219,448,000		$ 219,448,000			$ 219,973,000
Gain on debt extinguishment						0	$ 0	0	$ 4,626,000
Debenture Mature 2021 [Member]
Debt Instrument [Line Items]
Debt instrument commitments drawn						15,500,000		15,500,000
Long-term debt						8,500,000		$ 8,500,000
Preferred Securities [Member]
Debt Instrument [Line Items]
Maturity date								Sep. 30, 2037
Sale of preferred securities					$ 35,000,000.0
Issue of common stock | shares					1,083
Preferred securities outstanding						$ 33,000,000.0		$ 33,000,000.0
Preferred Securities [Member] | 90 day LIBOR [Member]
Debt Instrument [Line Items]
Basis spread on variable rate								(3.75%)
Preferred Securities [Member] | LIBOR Rate [Member]
Debt Instrument [Line Items]
Basis spread on variable rate								2.13%
Preferred Securities [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Aggregate principal amount of unsecured junior subordinated notes					$ 36,100,000
Small Business Administration Debentures and Borrowings [Member]
Debt Instrument [Line Items]
Debt instrument interest rate Percentage						3.25%		3.25%
Loan commitment term								4 years 6 months
Commitment fee percentage			1.00%					1.00%
Principal amount of loan																	$ 34,000,000.0
Extended maturity date								Apr. 30, 2024
Debt instrument commitments available						$ 9,500,000		$ 9,500,000
Debt instrument outstanding amount						68,800,000		68,800,000
Debt instrument remaining amount						7,800,000		$ 7,800,000
FSVC's [Member]
Debt Instrument [Line Items]
Principal amount of loan																	$ 33,500,000
7.25% Unsecured Senior Notes Due February 2026 [Member]
Debt Instrument [Line Items]
Aggregate principal amount												$ 3,000,000.0	$ 3,300,000
7.50% Unsecured Senior Notes Due December 2027 [Member]
Debt Instrument [Line Items]
Aggregate principal amount												$ 11,700,000
Privately Placed Notes [Member]
Debt Instrument [Line Items]
Aggregate principal amount		$ 25,000,000.0											$ 8,500,000	$ 33,600,000	$ 6,000,000.0	$ 30,000,000.0
Debt instrument interest rate Percentage		7.25%												7.50%		8.25%
Maturity date								2024
Maturity date								Dec. 31, 2027
Gain loss on sales of loans net										$ 4,100,000
Minimum [Member]
Debt Instrument [Line Items]
Time deposits						$ 250,000		$ 250,000
Brokerage [Member] | Maximum [Member]
Debt Instrument [Line Items]
Average brokerage fee percentage in relation to the maturity of deposits								0.15%

[1] Includes $3.3 million and $4.0 million of deferred financing costs as of September 30, 2022 and December 31, 2021. Refer to Note 5 for more details.