Condensed Parent Company Financial Statements - Summary of Cash Flow of Parent Company (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 212,465	$ 193,100	$ 167,630
Adjustments to reconcile to net cash provided by operating activities:
Amortization of stock-based compensation arrangements of subsidiaries	2,999	1,941	2,133
Other, net	(7,194)	(2,482)	6,783
Net cash provided by operating activities	233,045	226,272	203,934
INVESTING ACTIVITIES
Other, net	33,477	14,494	9,305
Net cash (used in) provided by investing activities	(669,705)	(1,519,168)	422,885
FINANCING ACTIVITIES
Common stock acquired	(1,820)		(11,663)
Net cash settlement of options			(5,479)
Cash dividends paid	(53,642)	(48,462)	(45,140)
Proceeds from issuance of subordinated notes, net of debt issuance costs			59,150
Net cash (used in) provided by financing activities	(334,787)	2,411,784	(193,709)
Net (decrease)/increase in cash, due from banks and interest-bearing deposits	(771,447)	1,118,888	433,110
Cash, due from banks and interest-bearing deposits at the beginning of the period	3,168,910	2,050,022	1,616,912
Cash, due from banks and interest-bearing deposits at the end of the period	2,397,463	3,168,910	2,050,022
SUPPLEMENTAL DISCLOSURE
Cash paid during the period for interest	191,760	42,930	11,993
Parent Company [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	212,465	193,100	167,630
Adjustments to reconcile to net cash provided by operating activities:
Equity in undistributed earnings of subsidiaries	(81,275)	(105,817)	(116,365)
Amortization of stock-based compensation arrangements of subsidiaries	2,910	1,833	2,048
Other, net	(655)	3,815	5,056
Net cash provided by operating activities	133,445	92,931	58,369
INVESTING ACTIVITIES
Payments for investments in subsidiaries	(6,100)	(94,967)	(9,000)
Other, net	(778)	(1,352)	4,429
Net cash (used in) provided by investing activities	(6,878)	(96,319)	(4,571)
FINANCING ACTIVITIES
Issuance of common stock	2,543	7,649	2,260
Common stock acquired	(1,820)		(11,663)
Net cash settlement of options			(5,479)
Cash dividends paid	(53,642)	(48,462)	(45,140)
Proceeds from issuance of subordinated notes, net of debt issuance costs			59,150
Net cash (used in) provided by financing activities	(52,919)	(40,813)	(872)
Net (decrease)/increase in cash, due from banks and interest-bearing deposits	73,648	(44,201)	52,926
Cash, due from banks and interest-bearing deposits at the beginning of the period	17,806	62,007	9,081
Cash, due from banks and interest-bearing deposits at the end of the period	91,454	17,806	62,007
SUPPLEMENTAL DISCLOSURE
Cash paid during the period for interest	4,122	4,122	3,130
Cash received during the period for income taxes, net	$ 1,746	$ 6,667	$ 4,411