Fair Value of Assets and Liabilities - Summary of Assets and Liabilities Measured at Fair Value on a Non-Recurring Basis (Detail) - USD ($)	Mar. 31, 2020		Dec. 31, 2019		Mar. 31, 2019	Dec. 31, 2018
Assets
Impaired loans	$ 108,515,000		$ 113,581,000
Loan collateral in process of foreclosure	46,817,000	[1]	52,711,000	[1]	$ 49,808,000	$ 49,495,000
Fair Value, Measurements, Nonrecurring [Member]
Assets
Equity investments	10,341,000		10,079,000
Impaired loans	62,004,000		34,915,000
Loan collateral in process of foreclosure	46,817,000		52,711,000
Total	119,162,000		97,705,000
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member]
Assets
Equity investments	10,341,000		10,079,000
Impaired loans	62,004,000		34,915,000
Loan collateral in process of foreclosure	46,817,000		52,711,000
Total	$ 119,162,000		$ 97,705,000

[1] Includes financed sales of this collateral to third parties that are reported separately from the loan portfolio, and that are conducted by the Bank of $9,157 as of March 31, 2020 and $8,163 as of December 31, 2019.