Parent Holding Company Information (Condensed) - Condensed Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2024	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Operating Activities
Net income	$ 61,754	$ 51,055	$ 44,708	$ 32,627	$ 54,316	$ 52,445	$ 54,955	$ 61,211	$ 190,144	$ 222,927	$ 303,202
Adjustments to reconcile net income to net cash provided by operating activities:
Stock-based compensation, net of tax benefits									5,694	5,929	5,366
Net cash provided by operating activities									258,037	500,715	470,660
Investing Activities
Net cash provided by (used in) investing activities									493,141	(207,492)	(1,351,782)
Financing Activities
Cash dividends paid									(150,034)	(146,690)	(157,540)
Tax withholding payments for stock-based compensation									(1,625)	(1,795)	(1,704)
Proceeds from stock option exercises									0	0	140
Net cash (used in) provided by financing activities									(1,257,112)	659,124	845,431
Net (decrease) increase in cash, cash equivalents and restricted cash									(505,934)	952,347	(35,691)
Cash, cash equivalents and restricted cash at beginning of period				1,354,342				401,995	1,354,342	401,995	437,686
Cash, cash equivalents and restricted cash at end of period	848,408				1,354,342				848,408	1,354,342	401,995
Parent Company
Operating Activities
Net income									190,144	222,927	303,202
Adjustments to reconcile net income to net cash provided by operating activities:
Subsidiary income less than (in excess of) dividends distributed									32,638	(58,835)	(191,258)
Stock-based compensation, net of tax benefits									1,762	1,742	1,685
Net change in other assets and other liabilities									200	7,788	1,794
Net cash provided by operating activities									224,744	173,622	115,423
Investing Activities
Net additions of premises and equipment									(5)	(3)	(4)
Proceeds from sale of marketable equity securities									107	0	63
Equity contributed to subsidiaries									(698)	0	0
Net cash provided by (used in) investing activities									(596)	(3)	59
Financing Activities
Cash dividends paid									(150,034)	(146,690)	(157,540)
Tax withholding payments for stock-based compensation									(1,625)	(1,795)	(1,704)
Proceeds from stock option exercises									0	0	140
Net cash (used in) provided by financing activities									(151,659)	(148,485)	(159,104)
Net (decrease) increase in cash, cash equivalents and restricted cash									72,489	25,134	(43,622)
Cash, cash equivalents and restricted cash at beginning of period				$ 100,818				$ 75,684	100,818	75,684	119,306
Cash, cash equivalents and restricted cash at end of period	$ 173,307				$ 100,818				$ 173,307	$ 100,818	$ 75,684