Loans and Allowance for Credit Losses (Allowance for Credit Losses by Portfolio Class) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance	$ 307,789	$ 342,065
Allowance for loan losses: Net provision for loan losses	59,103	(28,399)	$ (77,494)
Allowance for loan losses: Ending balance	307,907	307,789	342,065
Reserve for unfunded lending commitments: Beginning balance	33,309	29,334
Reserve for unfunded lending commitments: Provision for losses	(4,415)	3,975
Reserve for unfunded lending commitments: Ending balance	28,894	33,309	29,334
Total allowance for credit losses	336,801	341,098
Allowance for loan losses: Individually evaluated	1,666	476
Allowance for loan losses: Collectively evaluated	306,241	307,313
Reserve for unfunded lending commitments: Collectively evaluated	28,894	33,309
Loans: Individually evaluated for impairment	15,882	7,515
Loans: Collectively evaluated for impairment	23,906,035	23,106,531
Total loans	23,921,917	23,114,046
Non-Purchased Credit Impaired Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs	(75,423)	(22,590)
Allowance for loan losses: Recoveries	12,023	20,688
Allowance for loan losses: Net provision for loan losses	63,518	(32,374)
Total Commercial [Member] | Total Commercial And Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance	144,745	149,321
Allowance for loan losses: Ending balance	141,934	144,745	149,321
Reserve for unfunded lending commitments: Beginning balance	5,286	4,845
Reserve for unfunded lending commitments: Provision for losses	548	441
Reserve for unfunded lending commitments: Ending balance	5,834	5,286	4,845
Total allowance for credit losses	147,768	150,031
Allowance for loan losses: Individually evaluated	1,666	102
Allowance for loan losses: Collectively evaluated	140,268	144,643
Reserve for unfunded lending commitments: Collectively evaluated	5,834	5,286
Loans: Individually evaluated for impairment	15,882	2,168
Loans: Collectively evaluated for impairment	13,035,165	13,177,343
Total loans	13,051,047	13,179,511
Total Commercial [Member] | Non-Purchased Credit Impaired Loans [Member] | Total Commercial And Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs	(59,830)	(8,585)
Allowance for loan losses: Recoveries	7,109	12,545
Allowance for loan losses: Net provision for loan losses	49,910	(8,536)
Total Commercial [Member] | Commercial Non-Real Estate [Member] | Total Commercial And Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance	96,461	95,888
Allowance for loan losses: Ending balance	101,737	96,461	95,888
Reserve for unfunded lending commitments: Beginning balance	4,984	4,522
Reserve for unfunded lending commitments: Provision for losses	523	462
Reserve for unfunded lending commitments: Ending balance	5,507	4,984	4,522
Total allowance for credit losses	107,244	101,445
Allowance for loan losses: Individually evaluated	1,666	71
Allowance for loan losses: Collectively evaluated	100,071	96,390
Reserve for unfunded lending commitments: Collectively evaluated	5,507	4,984
Loans: Individually evaluated for impairment	15,882	1,248
Loans: Collectively evaluated for impairment	9,941,402	10,145,205
Total loans	9,957,284	10,146,453
Total Commercial [Member] | Commercial Non-Real Estate [Member] | Non-Purchased Credit Impaired Loans [Member] | Total Commercial And Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs	(59,830)	(7,637)
Allowance for loan losses: Recoveries	6,152	11,812
Allowance for loan losses: Net provision for loan losses	58,954	(3,602)
Total Commercial [Member] | Commercial Real Estate - Owner Occupied | Total Commercial And Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance	48,284	53,433
Allowance for loan losses: Ending balance	40,197	48,284	53,433
Reserve for unfunded lending commitments: Beginning balance	302	323
Reserve for unfunded lending commitments: Provision for losses	25	(21)
Reserve for unfunded lending commitments: Ending balance	327	302	323
Total allowance for credit losses	40,524	48,586
Allowance for loan losses: Individually evaluated		31
Allowance for loan losses: Collectively evaluated	40,197	48,253
Reserve for unfunded lending commitments: Collectively evaluated	327	302
Loans: Individually evaluated for impairment		920
Loans: Collectively evaluated for impairment	3,093,763	3,032,138
Total loans	3,093,763	3,033,058
Total Commercial [Member] | Commercial Real Estate - Owner Occupied | Non-Purchased Credit Impaired Loans [Member] | Total Commercial And Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs		(948)
Allowance for loan losses: Recoveries	957	733
Allowance for loan losses: Net provision for loan losses	(9,044)	(4,934)
Total Commercial [Member] | Commercial Real Estate - Income Producing [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance	71,961	108,058
Allowance for loan losses: Ending balance	74,539	71,961	108,058
Reserve for unfunded lending commitments: Beginning balance	1,395	1,694
Reserve for unfunded lending commitments: Provision for losses	(51)	(299)
Reserve for unfunded lending commitments: Ending balance	1,344	1,395	1,694
Total allowance for credit losses	75,883	73,356
Allowance for loan losses: Individually evaluated		16
Allowance for loan losses: Collectively evaluated	74,539	71,945
Reserve for unfunded lending commitments: Collectively evaluated	1,344	1,395
Loans: Individually evaluated for impairment		1,240
Loans: Collectively evaluated for impairment	3,986,943	3,559,751
Total loans	3,986,943	3,560,991
Total Commercial [Member] | Commercial Real Estate - Income Producing [Member] | Non-Purchased Credit Impaired Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs	(73)	(1,073)
Allowance for loan losses: Recoveries	14	878
Allowance for loan losses: Net provision for loan losses	2,637	(35,902)
Total Commercial [Member] | Construction and Land Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance	30,498	22,102
Allowance for loan losses: Ending balance	27,039	30,498	22,102
Reserve for unfunded lending commitments: Beginning balance	25,110	21,907
Reserve for unfunded lending commitments: Provision for losses	(5,091)	3,203
Reserve for unfunded lending commitments: Ending balance	20,019	25,110	21,907
Total allowance for credit losses	47,058	55,608
Allowance for loan losses: Individually evaluated		18
Allowance for loan losses: Collectively evaluated	27,039	30,480
Reserve for unfunded lending commitments: Collectively evaluated	20,019	25,110
Loans: Individually evaluated for impairment		116
Loans: Collectively evaluated for impairment	1,551,091	1,703,476
Total loans	1,551,091	1,703,592
Total Commercial [Member] | Construction and Land Development [Member] | Non-Purchased Credit Impaired Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs	(72)	(3)
Allowance for loan losses: Recoveries	11	134
Allowance for loan losses: Net provision for loan losses	(3,398)	8,265
Residential Mortgages [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance	32,464	30,623
Allowance for loan losses: Ending balance	38,983	32,464	30,623
Reserve for unfunded lending commitments: Beginning balance	31	22
Reserve for unfunded lending commitments: Provision for losses	(1)	9
Reserve for unfunded lending commitments: Ending balance	30	31	22
Total allowance for credit losses	39,013	32,495
Allowance for loan losses: Individually evaluated		239
Allowance for loan losses: Collectively evaluated	38,983	32,225
Reserve for unfunded lending commitments: Collectively evaluated	30	31
Loans: Individually evaluated for impairment		3,476
Loans: Collectively evaluated for impairment	3,886,072	3,089,129
Total loans	3,886,072	3,092,605
Residential Mortgages [Member] | Non-Purchased Credit Impaired Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs	(55)	(137)
Allowance for loan losses: Recoveries	1,278	1,749
Allowance for loan losses: Net provision for loan losses	5,296	229
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance	28,121	31,961
Allowance for loan losses: Ending balance	25,412	28,121	31,961
Reserve for unfunded lending commitments: Beginning balance	1,487	866
Reserve for unfunded lending commitments: Provision for losses	180	621
Reserve for unfunded lending commitments: Ending balance	1,667	1,487	$ 866
Total allowance for credit losses	27,079	29,608
Allowance for loan losses: Individually evaluated		101
Allowance for loan losses: Collectively evaluated	25,412	28,020
Reserve for unfunded lending commitments: Collectively evaluated	1,667	1,487
Loans: Individually evaluated for impairment		515
Loans: Collectively evaluated for impairment	1,446,764	1,576,832
Total loans	1,446,764	1,577,347
Consumer [Member] | Non-Purchased Credit Impaired Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs	(15,393)	(12,792)
Allowance for loan losses: Recoveries	3,611	5,382
Allowance for loan losses: Net provision for loan losses	$ 9,073	$ 3,570