Income Taxes - Schedule of Components of Investments in Qualified Affordable Housing Projects (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Tax credits and other tax benefits – decrease in tax expense	$ (4,200)	$ (2,546)	$ (1,993)
Amortization – increase in tax expense	$ 3,581	$ 2,705	$ 1,814