Condensed Parent Company Financial Statements - Schedule of Condensed Cash Flow Statement (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
OPERATING ACTIVITIES
Net Income (Loss)	$ 159,032	$ 192,113	$ 242,260
Adjustments to reconcile net income to net cash provided by operating activities:
Net change in other assets	(30,029)	(63,074)	60,503
Net securities (gains) losses	(900)	1,777	(1,113)
Other—net	(155)	(3,075)	(6,549)
Net cash provided by operating activities	169,322	204,140	336,297
INVESTING ACTIVITIES
Proceeds from sales-securities available-for-sale	30,987	0	0
Net cash used in investing activities	(535,224)	(1,068,160)	(328,496)
FINANCING ACTIVITIES
Repayment of subordinated and junior subordinated debt	(2,294)		(60,000)
Issuance of subordinated debt		147,702
Treasury shares purchased—net	(3,508)	(116,047)	(179,882)
Dividends paid to common and preferred shareholders	(82,290)	(81,325)	(86,484)
Net cash provided by financing activities	552,874	21,073	338,110
Net increase (decrease) in cash, cash equivalents and restricted cash	186,972	(842,947)	345,911
Cash, cash equivalents and restricted cash at beginning of the year	408,411	1,251,358	905,447
Cash, cash equivalents and restricted cash at end of the year	595,383	408,411	1,251,358
Parent Company [Member]
OPERATING ACTIVITIES
Net Income (Loss)	159,032	192,113	242,260
Adjustments to reconcile net income to net cash provided by operating activities:
(Equity in undistributed net income) excess dividends of subsidiaries	(91,582)	(30,918)	2,832
Net change in other assets	1,122	582	(1,453)
Other—net	7,669	6,941	7,984
Net cash provided by operating activities	76,241	168,718	251,623
INVESTING ACTIVITIES
Acquisitions and additional capitalization of subsidiaries, net of cash acquired		(100)
Net cash used in investing activities		(100)
FINANCING ACTIVITIES
Repayment of subordinated and junior subordinated debt	(2,294)		(35,000)
Issuance of subordinated debt		147,702
Treasury shares purchased—net	(3,508)	(116,047)	(179,882)
Dividends paid to common and preferred shareholders	(92,415)	(91,450)	(96,609)
Net cash provided by financing activities	(98,217)	(59,795)	(311,491)
Net increase (decrease) in cash, cash equivalents and restricted cash	(21,976)	108,823	(59,868)
Cash, cash equivalents and restricted cash at beginning of the year	272,179	163,356	223,224
Cash, cash equivalents and restricted cash at end of the year	$ 250,203	$ 272,179	$ 163,356