Parent Holding Company Information (Condensed) - Condensed Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Activities
Net income	$ 79,677	$ 79,338	$ 76,392	$ 67,795	$ 50,709	$ 75,619	$ 77,627	$ 80,802	$ 303,202	$ 284,757	$ 266,400
Adjustments to reconcile net income to net cash provided by operating activities:
Stock-based compensation, net of tax benefits									5,366	4,349	3,629
Net cash provided by operating activities									470,660	572,049	189,545
Investing Activities
Net additions of premises and equipment									(23,238)	(9,436)	(11,717)
Net cash used in investing activities									(1,351,782)	(3,906,701)	(3,563,696)
Financing Activities
Net decrease in other borrowed funds									9,120	3,526	564
Cash dividends paid									(157,540)	(145,557)	(131,263)
Tax withholding payments for stock-based compensation									(1,704)	(1,553)	(1,082)
Proceeds from stock option exercises									140	265	993
Net cash provided by financing activities									845,431	3,139,196	3,676,332
Net (decrease) increase in cash, cash equivalents and restricted cash									(35,691)	(195,456)	302,181
Cash, cash equivalents and restricted cash at beginning of period				437,686				633,142	437,686	633,142	330,961
Cash, cash equivalents and restricted cash at end of period	401,995				437,686				401,995	437,686	633,142
Parent Company
Operating Activities
Net income									303,202	284,757	266,400
Adjustments to reconcile net income to net cash provided by operating activities:
Subsidiary income in excess of dividends distributed									(191,258)	(91,336)	(87,703)
Stock-based compensation, net of tax benefits									1,685	1,628	1,216
Net change in other assets and other liabilities									1,794	(7,245)	(7,222)
Net cash provided by operating activities									115,423	187,804	172,691
Investing Activities
Net additions of premises and equipment									(4)	(13)	(111)
Proceeds from sale of marketable equity securities									63	186	0
Equity received from (contributed to) subsidiaries									0	248	(13,638)
Net cash used in investing activities									59	421	(13,749)
Financing Activities
Net decrease in other borrowed funds									0	(7,500)	0
Cash dividends paid									(157,540)	(145,557)	(131,263)
Tax withholding payments for stock-based compensation									(1,704)	(1,553)	(1,082)
Proceeds from stock option exercises									140	265	993
Net cash provided by financing activities									(159,104)	(154,345)	(131,352)
Net (decrease) increase in cash, cash equivalents and restricted cash									(43,622)	33,880	27,590
Cash, cash equivalents and restricted cash at beginning of period				$ 119,306				$ 85,426	119,306	85,426	57,836
Cash, cash equivalents and restricted cash at end of period	$ 75,684				$ 119,306				$ 75,684	$ 119,306	$ 85,426