Low Income Housing Tax Credits and Other Tax Credit Investments - Summary of the Company's Investments in Low Income Housing Projects Accounted for Using the Proportional Amortization Method (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Investments in Affordable Housing Projects [Abstract]
Current recorded investment included in other assets	$ 62,904		$ 58,504
Commitments to fund qualified affordable housing projects included in recorded investment noted above	34,430		$ 31,487
Tax credits and benefits recognized	1,464	$ 1,519
Amortization expense included in income tax expense	$ 1,264	$ 1,191