Condensed Parent Company Financial Statements - Summary of Cash Flow of Parent Company (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 193,100	$ 167,630	$ 99,586
Adjustments to reconcile to net cash provided by operating activities:
Amortization of stock-based compensation arrangements of subsidiaries	1,941	2,133	1,516
Other, net	(2,482)	6,783	7,818
Net cash provided by operating activities	226,272	203,934	154,854
INVESTING ACTIVITIES
Other, net	14,494	9,305	7,820
Net cash (used in) provided by investing activities	(1,519,168)	422,885	(898,506)
FINANCING ACTIVITIES
Common stock acquired		(11,663)	(3,098)
Net cash settlement of options		(5,479)
Cash dividends paid	(48,462)	(45,140)	(42,472)
Proceeds from issuance of subordinated notes, net of debt issuance costs		59,150
Net cash provided by (used in) financing activities	2,411,784	(193,709)	492,283
Net increase/(decrease) in cash, due from banks and interest-bearing deposits	1,118,888	433,110	(251,369)
Cash, due from banks and interest-bearing deposits at the beginning of the period	2,050,022	1,616,912	1,868,281
Cash, due from banks and interest-bearing deposits at the end of the period	3,168,910	2,050,022	1,616,912
SUPPLEMENTAL DISCLOSURE
Cash paid during the period for interest	42,930	11,993	22,056
Cash received during the period for income taxes, net	34,640	30,600	26,525
Parent Company [Member]
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	193,100	167,630	99,586
Adjustments to reconcile to net cash provided by operating activities:
Equity in undistributed earnings of subsidiaries	(105,817)	(116,365)	(51,955)
Amortization of stock-based compensation arrangements of subsidiaries	1,833	2,048	1,456
Other, net	3,815	5,056	188
Net cash provided by operating activities	92,931	58,369	49,275
INVESTING ACTIVITIES
Payments for investments in subsidiaries	(94,967)	(9,000)	(1,000)
Other, net	(1,352)	4,429	(1,175)
Net cash (used in) provided by investing activities	(96,319)	(4,571)	(2,175)
FINANCING ACTIVITIES
Issuance of common stock	7,649	2,260	1,790
Common stock acquired		(11,663)	(3,098)
Net cash settlement of options		(5,479)
Cash dividends paid	(48,462)	(45,140)	(42,472)
Proceeds from issuance of subordinated notes, net of debt issuance costs		59,150
Net cash provided by (used in) financing activities	(40,813)	(872)	(43,780)
Net increase/(decrease) in cash, due from banks and interest-bearing deposits	(44,201)	52,926	3,320
Cash, due from banks and interest-bearing deposits at the beginning of the period	62,007	9,081	5,761
Cash, due from banks and interest-bearing deposits at the end of the period	17,806	62,007	9,081
SUPPLEMENTAL DISCLOSURE
Cash paid during the period for interest	4,122	3,130	1,966
Cash received during the period for income taxes, net	$ 6,667	$ 4,411	$ 2,812