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, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
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	$ 7,633	$ (9,761)	13,653	(32,288)
Allowance for loan losses: Ending balance	314,496	308,175	314,496	308,175
Reserve for unfunded lending commitments: Beginning balance			33,309	29,334
Reserve for unfunded lending commitments: Provision for losses			2,149	1,969
Reserve for unfunded lending commitments: Ending balance	31,160	31,303	31,160	31,303
Total allowance for credit losses	345,656	339,478	345,656	339,478
Allowance for loan losses: Individually evaluated	7,501	636	7,501	636
Allowance for loan losses: Collectively evaluated	306,995	307,539	306,995	307,539
Reserve for unfunded lending commitments: Collectively evaluated	31,160	31,303	31,160	31,303
Loans: Individually evaluated for impairment	37,507	8,801	37,507	8,801
Loans: Collectively evaluated for impairment	23,752,379	21,837,267	23,752,379	21,837,267
Total loans	23,789,886	21,846,068	23,789,886	21,846,068	$ 23,114,046
Non-Purchased Credit Impaired Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs			(14,588)	(11,360)
Allowance for loan losses: Recoveries			5,493	11,727
Allowance for loan losses: Net provision for loan losses			15,802	(34,257)
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	77,141	82,951	77,141	82,951
Reserve for unfunded lending commitments: Beginning balance			1,395	1,694
Reserve for unfunded lending commitments: Provision for losses			28	274
Reserve for unfunded lending commitments: Ending balance	1,423	1,420	1,423	1,420
Total allowance for credit losses	78,564	84,371	78,564	84,371
Allowance for loan losses: Individually evaluated		18		18
Allowance for loan losses: Collectively evaluated	77,141	82,933	77,141	82,933
Reserve for unfunded lending commitments: Collectively evaluated	1,423	1,420	1,423	1,420
Loans: Individually evaluated for impairment		1,289		1,289
Loans: Collectively evaluated for impairment	3,762,428	3,639,954	3,762,428	3,639,954
Total loans	3,762,428	3,641,243	3,762,428	3,641,243	3,560,991
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	31,344	24,703	31,344	24,703
Reserve for unfunded lending commitments: Beginning balance			25,110	21,907
Reserve for unfunded lending commitments: Provision for losses			2,227	(1,598)
Reserve for unfunded lending commitments: Ending balance	22,883	23,505	22,883	23,505
Total allowance for credit losses	54,227	48,208	54,227	48,208
Allowance for loan losses: Individually evaluated		19		19
Allowance for loan losses: Collectively evaluated	31,344	24,684	31,344	24,684
Reserve for unfunded lending commitments: Collectively evaluated	22,883	23,505	22,883	23,505
Loans: Individually evaluated for impairment		120		120
Loans: Collectively evaluated for impairment	1,768,252	1,408,607	1,768,252	1,408,607
Total loans	1,768,252	1,408,727	1,768,252	1,408,727	1,703,592
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			(73)	(1,066)
Allowance for loan losses: Recoveries			10	878
Allowance for loan losses: Net provision for loan losses			5,243	(24,919)
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			(72)	(3)
Allowance for loan losses: Recoveries			6	126
Allowance for loan losses: Net provision for loan losses			912	2,478
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	142,490	142,434	142,490	142,434
Reserve for unfunded lending commitments: Beginning balance			5,286	4,845
Reserve for unfunded lending commitments: Provision for losses			(39)	91
Reserve for unfunded lending commitments: Ending balance	5,325	4,936	5,325	4,936
Total allowance for credit losses	147,815	147,370	147,815	147,370
Allowance for loan losses: Individually evaluated	7,501	107	7,501	107
Allowance for loan losses: Collectively evaluated	134,989	142,327	134,989	142,327
Reserve for unfunded lending commitments: Collectively evaluated	5,325	4,936	5,325	4,936
Loans: Individually evaluated for impairment	36,372	2,496	36,372	2,496
Loans: Collectively evaluated for impairment	13,136,389	12,607,070	13,136,389	12,607,070
Total loans	13,172,761	12,609,566	13,172,761	12,609,566	13,179,511
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			96,461	95,888
Allowance for loan losses: Ending balance	96,195	92,819	96,195	92,819
Reserve for unfunded lending commitments: Beginning balance			4,984	4,522
Reserve for unfunded lending commitments: Provision for losses			(12)	51
Reserve for unfunded lending commitments: Ending balance	4,996	4,573	4,996	4,573
Total allowance for credit losses	101,191	97,392	101,191	97,392
Allowance for loan losses: Individually evaluated	7,501	76	7,501	76
Allowance for loan losses: Collectively evaluated	88,694	92,743	88,694	92,743
Reserve for unfunded lending commitments: Collectively evaluated	4,996	4,573	4,996	4,573
Loans: Individually evaluated for impairment	35,697	1,559	35,697	1,559
Loans: Collectively evaluated for impairment	10,078,235	9,643,533	10,078,235	9,643,533
Total loans	10,113,932	9,645,092	10,113,932	9,645,092	10,146,453
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			48,284	53,433
Allowance for loan losses: Ending balance	46,295	49,615	46,295	49,615
Reserve for unfunded lending commitments: Beginning balance			302	323
Reserve for unfunded lending commitments: Provision for losses			27	40
Reserve for unfunded lending commitments: Ending balance	329	363	329	363
Total allowance for credit losses	46,624	49,978	46,624	49,978
Allowance for loan losses: Individually evaluated		31		31
Allowance for loan losses: Collectively evaluated	46,295	49,584	46,295	49,584
Reserve for unfunded lending commitments: Collectively evaluated	329	363	329	363
Loans: Individually evaluated for impairment	675	937	675	937
Loans: Collectively evaluated for impairment	3,058,154	2,963,537	3,058,154	2,963,537
Total loans	3,058,829	2,964,474	3,058,829	2,964,474	3,033,058
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			(7,503)	(4,604)
Allowance for loan losses: Recoveries			3,044	7,094
Allowance for loan losses: Net provision for loan losses			2,204	(9,377)
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			(7,503)	(3,747)
Allowance for loan losses: Recoveries			2,694	6,603
Allowance for loan losses: Net provision for loan losses			4,543	(5,925)
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				(857)
Allowance for loan losses: Recoveries			350	491
Allowance for loan losses: Net provision for loan losses			(2,339)	(3,452)
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	36,597	28,584	36,597	28,584
Reserve for unfunded lending commitments: Beginning balance			31	22
Reserve for unfunded lending commitments: Provision for losses			(8)	2
Reserve for unfunded lending commitments: Ending balance	23	24	23	24
Total allowance for credit losses	36,620	28,608	36,620	28,608
Allowance for loan losses: Individually evaluated		322		322
Allowance for loan losses: Collectively evaluated	36,597	28,262	36,597	28,262
Reserve for unfunded lending commitments: Collectively evaluated	23	24	23	24
Loans: Individually evaluated for impairment	1,135	3,991	1,135	3,991
Loans: Collectively evaluated for impairment	3,580,379	2,611,816	3,580,379	2,611,816
Total loans	3,581,514	2,615,807	3,581,514	2,615,807	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			(28)	(60)
Allowance for loan losses: Recoveries			480	527
Allowance for loan losses: Net provision for loan losses			3,681	(2,506)
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	26,924	29,503	26,924	29,503
Reserve for unfunded lending commitments: Beginning balance			1,487	866
Reserve for unfunded lending commitments: Provision for losses			(19)	552
Reserve for unfunded lending commitments: Ending balance	1,506	1,418	1,506	1,418
Total allowance for credit losses	28,430	30,921	28,430	30,921
Allowance for loan losses: Individually evaluated		170		170
Allowance for loan losses: Collectively evaluated	26,924	29,333	26,924	29,333
Reserve for unfunded lending commitments: Collectively evaluated	1,506	1,418	1,506	1,418
Loans: Individually evaluated for impairment		905		905
Loans: Collectively evaluated for impairment	1,504,931	1,569,820	1,504,931	1,569,820
Total loans	$ 1,504,931	$ 1,570,725	1,504,931	1,570,725	$ 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			(6,912)	(5,627)
Allowance for loan losses: Recoveries			1,953	3,102
Allowance for loan losses: Net provision for loan losses			$ 3,762	$ 67