Loans and Allowance for Credit Losses (Allowance for Credit Losses by Portfolio Class) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance			$ 307,907	$ 307,789
Allowance for loan losses: Net provision for loan losses	$ 8,723	$ 7,633	21,691	13,653
Allowance for loan losses: Ending balance	316,148	314,496	316,148	314,496
Reserve for unfunded lending commitments: Beginning balance			28,894	33,309
Reserve for unfunded lending commitments: Provision for losses			(2,815)	(2,149)
Reserve for unfunded lending commitments: Ending balance	26,079	31,160	26,079	31,160
Total allowance for credit losses	342,227	345,656	342,227	345,656
Allowance for loan losses: Individually evaluated	236	0	236	0
Allowance for loan losses: Collectively evaluated	315,912	306,995	315,912	306,995
Reserve for unfunded lending commitments: Individually evaluated	294	7,501	294	7,501
Reserve for unfunded lending commitments: Collectively evaluated	25,785	31,160	25,785	31,160
Loans: Individually evaluated for impairment	40,099	37,507	40,099	37,507
Loans: Collectively evaluated for impairment	23,871,517	23,752,379	23,871,517	23,752,379
Total loans	23,911,616	23,789,886	23,911,616	23,789,886	$ 23,921,917
Non-Purchased Credit Impaired Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs			(35,317)	(14,588)
Allowance for loan losses: Recoveries			19,052	5,493
Allowance for loan losses: Net provision for loan losses			24,506	15,802
Total Commercial [Member] | Commercial Real Estate - Income Producing [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance			74,539	71,961
Allowance for loan losses: Ending balance	77,643	77,141	77,643	77,141
Reserve for unfunded lending commitments: Beginning balance			1,344	1,395
Reserve for unfunded lending commitments: Provision for losses			(376)	28
Reserve for unfunded lending commitments: Ending balance	968	1,423	968	1,423
Total allowance for credit losses	78,611	78,564	78,611	78,564
Allowance for loan losses: Individually evaluated		0		0
Allowance for loan losses: Collectively evaluated	77,643	77,141	77,643	77,141
Reserve for unfunded lending commitments: Individually evaluated		0		0
Reserve for unfunded lending commitments: Collectively evaluated	968	1,423	968	1,423
Loans: Individually evaluated for impairment	23,436	0	23,436	0
Loans: Collectively evaluated for impairment	4,030,376	3,762,428	4,030,376	3,762,428
Total loans	4,053,812	3,762,428	4,053,812	3,762,428	3,986,943
Total Commercial [Member] | Construction and Land Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance			27,039	30,498
Allowance for loan losses: Ending balance	27,271	31,344	27,271	31,344
Reserve for unfunded lending commitments: Beginning balance			20,019	25,110
Reserve for unfunded lending commitments: Provision for losses			(2,693)	(2,227)
Reserve for unfunded lending commitments: Ending balance	17,326	22,883	17,326	22,883
Total allowance for credit losses	44,597	54,227	44,597	54,227
Allowance for loan losses: Individually evaluated		0		0
Allowance for loan losses: Collectively evaluated	27,271	31,344	27,271	31,344
Reserve for unfunded lending commitments: Individually evaluated		0		0
Reserve for unfunded lending commitments: Collectively evaluated	17,326	22,883	17,326	22,883
Loans: Individually evaluated for impairment	928	0	928	0
Loans: Collectively evaluated for impairment	1,527,465	1,768,252	1,527,465	1,768,252
Total loans	1,528,393	1,768,252	1,528,393	1,768,252	1,551,091
Total Commercial [Member] | Non-Purchased Credit Impaired Loans [Member] | Commercial Real Estate - Income Producing [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs			(8,819)	(73)
Allowance for loan losses: Recoveries			5	10
Allowance for loan losses: Net provision for loan losses			11,918	5,243
Total Commercial [Member] | Non-Purchased Credit Impaired Loans [Member] | Construction and Land Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs			(225)	(72)
Allowance for loan losses: Recoveries			62	6
Allowance for loan losses: Net provision for loan losses			395	912
Total Commercial [Member] | Total Commercial And Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance			141,934	144,745
Allowance for loan losses: Ending balance	144,438	142,490	144,438	142,490
Reserve for unfunded lending commitments: Beginning balance			5,834	5,286
Reserve for unfunded lending commitments: Provision for losses			336	39
Reserve for unfunded lending commitments: Ending balance	6,170	5,325	6,170	5,325
Total allowance for credit losses	150,608	147,815	150,608	147,815
Allowance for loan losses: Individually evaluated	236	0	236	0
Allowance for loan losses: Collectively evaluated	144,202	134,989	144,202	134,989
Reserve for unfunded lending commitments: Individually evaluated	294	7,501	294	7,501
Reserve for unfunded lending commitments: Collectively evaluated	5,876	5,325	5,876	5,325
Loans: Individually evaluated for impairment	14,917	36,372	14,917	36,372
Loans: Collectively evaluated for impairment	12,927,100	13,136,389	12,927,100	13,136,389
Total loans	12,942,017	13,172,761	12,942,017	13,172,761	13,051,047
Total Commercial [Member] | Total Commercial And Industrial [Member] | Commercial Non-Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance			101,737	96,461
Allowance for loan losses: Ending balance	105,873	96,195	105,873	96,195
Reserve for unfunded lending commitments: Beginning balance			5,507	4,984
Reserve for unfunded lending commitments: Provision for losses			355	12
Reserve for unfunded lending commitments: Ending balance	5,862	4,996	5,862	4,996
Total allowance for credit losses	111,735	101,191	111,735	101,191
Allowance for loan losses: Individually evaluated	180	0	180	0
Allowance for loan losses: Collectively evaluated	105,693	88,694	105,693	88,694
Reserve for unfunded lending commitments: Individually evaluated	294	7,501	294	7,501
Reserve for unfunded lending commitments: Collectively evaluated	5,568	4,996	5,568	4,996
Loans: Individually evaluated for impairment	11,578	35,697	11,578	35,697
Loans: Collectively evaluated for impairment	9,836,181	10,078,235	9,836,181	10,078,235
Total loans	9,847,759	10,113,932	9,847,759	10,113,932	9,957,284
Total Commercial [Member] | Total Commercial And Industrial [Member] | Commercial Real Estate - Owner Occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance			40,197	48,284
Allowance for loan losses: Ending balance	38,565	46,295	38,565	46,295
Reserve for unfunded lending commitments: Beginning balance			327	302
Reserve for unfunded lending commitments: Provision for losses			(19)	27
Reserve for unfunded lending commitments: Ending balance	308	329	308	329
Total allowance for credit losses	38,873	46,624	38,873	46,624
Allowance for loan losses: Individually evaluated	56	0	56	0
Allowance for loan losses: Collectively evaluated	38,509	46,295	38,509	46,295
Reserve for unfunded lending commitments: Collectively evaluated	308	329	308	329
Loans: Individually evaluated for impairment	3,339	675	3,339	675
Loans: Collectively evaluated for impairment	3,090,919	3,058,154	3,090,919	3,058,154
Total loans	3,094,258	3,058,829	3,094,258	3,058,829	3,093,763
Total Commercial [Member] | Total Commercial And Industrial [Member] | Non-Purchased Credit Impaired Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs			(17,304)	(7,503)
Allowance for loan losses: Recoveries			16,915	3,044
Allowance for loan losses: Net provision for loan losses			2,893	2,204
Total Commercial [Member] | Total Commercial And Industrial [Member] | Non-Purchased Credit Impaired Loans [Member] | Commercial Non-Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs			(17,304)	(7,503)
Allowance for loan losses: Recoveries			16,054	2,694
Allowance for loan losses: Net provision for loan losses			5,386	4,543
Total Commercial [Member] | Total Commercial And Industrial [Member] | Non-Purchased Credit Impaired Loans [Member] | Commercial Real Estate - Owner Occupied [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs				0
Allowance for loan losses: Recoveries			861	350
Allowance for loan losses: Net provision for loan losses			(2,493)	(2,339)
Residential Mortgages [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance			38,983	32,464
Allowance for loan losses: Ending balance	41,693	36,597	41,693	36,597
Reserve for unfunded lending commitments: Beginning balance			30	31
Reserve for unfunded lending commitments: Provision for losses			(19)	(8)
Reserve for unfunded lending commitments: Ending balance	11	23	11	23
Total allowance for credit losses	41,704	36,620	41,704	36,620
Allowance for loan losses: Individually evaluated		0		0
Allowance for loan losses: Collectively evaluated	41,693	36,597	41,693	36,597
Reserve for unfunded lending commitments: Individually evaluated		0		0
Reserve for unfunded lending commitments: Collectively evaluated	11	23	11	23
Loans: Individually evaluated for impairment		1,135		1,135
Loans: Collectively evaluated for impairment	4,000,211	3,580,379	4,000,211	3,580,379
Total loans	4,000,211	3,581,514	4,000,211	3,581,514	3,886,072
Residential Mortgages [Member] | Non-Purchased Credit Impaired Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs			(67)	(28)
Allowance for loan losses: Recoveries			296	480
Allowance for loan losses: Net provision for loan losses			2,481	3,681
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance			25,412	28,121
Allowance for loan losses: Ending balance	25,103	26,924	25,103	26,924
Reserve for unfunded lending commitments: Beginning balance			1,667	1,487
Reserve for unfunded lending commitments: Provision for losses			(63)	19
Reserve for unfunded lending commitments: Ending balance	1,604	1,506	1,604	1,506
Total allowance for credit losses	26,707	28,430	26,707	28,430
Allowance for loan losses: Individually evaluated		0		0
Allowance for loan losses: Collectively evaluated	25,103	26,924	25,103	26,924
Reserve for unfunded lending commitments: Individually evaluated		0		0
Reserve for unfunded lending commitments: Collectively evaluated	1,604	1,506	1,604	1,506
Loans: Individually evaluated for impairment	818	0	818	0
Loans: Collectively evaluated for impairment	1,386,365	1,504,931	1,386,365	1,504,931
Total loans	$ 1,387,183	$ 1,504,931	1,387,183	1,504,931	$ 1,446,764
Consumer [Member] | Non-Purchased Credit Impaired Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs			(8,902)	(6,912)
Allowance for loan losses: Recoveries			1,774	1,953
Allowance for loan losses: Net provision for loan losses			$ 6,819	$ 3,762