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		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Investments in Affordable Housing Projects [Abstract]
Current recorded investment included in other assets	$ 70,184		$ 70,184		$ 58,504
Commitments to fund qualified affordable housing projects included in recorded investment noted above	41,380		41,380		$ 31,487
Tax credits and benefits recognized	1,523	$ 1,539	2,987	$ 3,058
Amortization expense included in income tax expense	$ 1,495	$ 1,261	$ 2,759	$ 2,452