Non-interest Income and Expense - Components of Non Interest Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Other Income and Expenses [Abstract]
Base salaries, net of deferred loan origination costs	$ 23,616	$ 22,377	$ 70,675	$ 62,762
Incentive compensation	4,391	4,832	11,663	11,697
Benefits and other compensation costs	6,456	6,319	19,402	18,782
Total salaries and benefits expense	34,463	33,528	101,740	93,241
Occupancy	3,948	3,965	12,099	11,536
Data processing and software	5,246	3,449	13,916	10,558
Equipment	1,503	1,422	4,322	4,208
Intangible amortization	1,590	1,702	4,902	4,632
Advertising	881	990	2,656	2,445
ATM and POS network charges	1,606	1,694	5,217	4,850
Professional fees	1,752	1,172	5,326	3,281
Telecommunications	567	575	1,971	1,660
Regulatory assessments and insurance	1,194	828	3,979	2,327
Merger and acquisition expense	0	0	0	6,253
Postage	306	287	916	828
Operational losses	474	492	1,999	765
Courier service	492	497	1,314	1,397
Gain on sale or acquisition of foreclosed assets	(152)	(148)	(152)	(246)
Gain on disposal of fixed assets	4	4	22	(1,069)
Other miscellaneous expense	4,004	4,008	12,688	10,510
Total other non-interest expense	23,415	20,937	71,175	63,935
Total non-interest expense	$ 57,878	$ 54,465	$ 172,915	$ 157,176