Other Operating Expenses - Schedule of Other Operating Expenses (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating Costs And Expenses [Abstract]
Franchise and other miscellaneous taxes	$ 14,112	$ 12,813	$ 9,847
Consulting, regulatory and advisory fees	11,717	8,993	6,976
ATM and electronic banking interchange expenses	8,365	6,931	5,718
Postage and courier expenses	5,028	5,334	4,143
Supplies	4,561	4,499	3,180
Legal fees	3,307	3,054	2,778
Communications	4,292	3,720	2,569
Other real estate owned and foreclosure expenses	(108)	397	831
Other	19,474	16,915	14,679
Total other operating expenses	$ 70,748	$ 62,656	$ 50,721