Fair Value of Assets and Liabilities - Summary of Assets and Liabilities Measured at Fair Value on a Non-Recurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2023		Jun. 30, 2023	Dec. 31, 2022		Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021
Assets
Equity investments	$ 1,700			$ 1,700
Impaired loans	15,600			19,500
Loan collateral in process of foreclosure	15,923	[1]	$ 16,803	21,819	[1]	$ 24,331	$ 26,974	$ 37,430
Fair Value, Nonrecurring
Assets
Equity investments	10,542			10,293
Impaired loans	20,648			32,133
Loan collateral in process of foreclosure	15,923			21,819
Total	47,113			64,245
Fair Value, Nonrecurring | Level 3 [Member]
Assets
Equity investments	10,542			10,293
Impaired loans	20,648			32,133
Loan collateral in process of foreclosure	15,923			21,819
Total	$ 47,113			$ 64,245

[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.