Loans and Allowance for Credit Losses (Allowance for Credit Losses by Portfolio Class) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance	$ 318,882	$ 307,907
Allowance for loan losses: Net provision for loan losses	10,462	12,968
Allowance for loan losses: Ending balance	318,119	313,726
Reserve for unfunded lending commitments: Beginning balance	24,053	28,894
Reserve for unfunded lending commitments: Provision for losses	978	(1,831)
Reserve for unfunded lending commitments: Ending balance	25,031	27,063
Total allowance for credit losses	343,150	340,789
Allowance for credit losses: Individually evaluated	11,404
Allowance for credit losses: Collectively evaluated	331,746	340,789
Non-Purchased Credit Impaired Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs	(13,293)	(23,366)
Allowance for loan losses: Recoveries	3,046	14,386
Allowance for loan losses: Net provision for loan losses	9,484	14,799
Total Commercial [Member] | Commercial Real Estate - Income Producing [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance	71,975	74,539
Allowance for loan losses: Ending balance	70,379	77,877
Reserve for unfunded lending commitments: Beginning balance	642	1,344
Reserve for unfunded lending commitments: Provision for losses	(198)	(352)
Reserve for unfunded lending commitments: Ending balance	444	992
Total allowance for credit losses	70,823	78,869
Allowance for credit losses: Collectively evaluated	70,823	78,869
Total Commercial [Member] | Construction and Land Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance	21,158	27,039
Allowance for loan losses: Ending balance	20,208	25,838
Reserve for unfunded lending commitments: Beginning balance	14,639	20,019
Reserve for unfunded lending commitments: Provision for losses	696	(1,615)
Reserve for unfunded lending commitments: Ending balance	15,335	18,404
Total allowance for credit losses	35,543	44,242
Allowance for credit losses: Collectively evaluated	35,543	44,242
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	(34)	(8,819)
Allowance for loan losses: Recoveries		3
Allowance for loan losses: Net provision for loan losses	(1,562)	12,154
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	(8)	(75)
Allowance for loan losses: Recoveries	110	61
Allowance for loan losses: Net provision for loan losses	(1,052)	(1,187)
Total Commercial [Member] | Total Commercial And Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance	157,354	141,934
Allowance for loan losses: Ending balance	158,348	143,636
Reserve for unfunded lending commitments: Beginning balance	6,750	5,834
Reserve for unfunded lending commitments: Provision for losses	502	152
Reserve for unfunded lending commitments: Ending balance	7,252	5,986
Total allowance for credit losses	165,600	149,622
Allowance for credit losses: Individually evaluated	10,455
Allowance for credit losses: Collectively evaluated	155,145	149,622
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	121,090	101,737
Allowance for loan losses: Ending balance	122,215	104,358
Reserve for unfunded lending commitments: Beginning balance	6,441	5,507
Reserve for unfunded lending commitments: Provision for losses	515	192
Reserve for unfunded lending commitments: Ending balance	6,956	5,699
Total allowance for credit losses	129,171	110,057
Allowance for credit losses: Individually evaluated	10,406
Allowance for credit losses: Collectively evaluated	118,765	110,057
Total Commercial [Member] | Total Commercial And Industrial [Member] | Commercial Real Estate - Owner Occupied
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance	36,264	40,197
Allowance for loan losses: Ending balance	36,133	39,278
Reserve for unfunded lending commitments: Beginning balance	309	327
Reserve for unfunded lending commitments: Provision for losses	(13)	(40)
Reserve for unfunded lending commitments: Ending balance	296	287
Total allowance for credit losses	36,429	39,565
Allowance for credit losses: Individually evaluated	49
Allowance for credit losses: Collectively evaluated	36,380	39,565
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	(8,873)	(9,630)
Allowance for loan losses: Recoveries	1,745	13,206
Allowance for loan losses: Net provision for loan losses	8,122	(1,874)
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	(6,132)	(9,630)
Allowance for loan losses: Recoveries	1,650	13,104
Allowance for loan losses: Net provision for loan losses	5,607	(853)
Total Commercial [Member] | Total Commercial And Industrial [Member] | Non-Purchased Credit Impaired Loans [Member] | Commercial Real Estate - Owner Occupied
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs	(2,741)
Allowance for loan losses: Recoveries	95	102
Allowance for loan losses: Net provision for loan losses	2,515	(1,021)
Residential Mortgages [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance	42,445	38,983
Allowance for loan losses: Ending balance	43,200	41,158
Reserve for unfunded lending commitments: Beginning balance	4	30
Reserve for unfunded lending commitments: Provision for losses	(1)	(8)
Reserve for unfunded lending commitments: Ending balance	3	22
Total allowance for credit losses	43,203	41,180
Allowance for credit losses: Individually evaluated	752
Allowance for credit losses: Collectively evaluated	42,451	41,180
Residential Mortgages [Member] | Non-Purchased Credit Impaired Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs	(167)	(56)
Allowance for loan losses: Recoveries	387	202
Allowance for loan losses: Net provision for loan losses	535	2,029
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Beginning balance	25,950	25,412
Allowance for loan losses: Ending balance	25,984	25,217
Reserve for unfunded lending commitments: Beginning balance	2,018	1,667
Reserve for unfunded lending commitments: Provision for losses	(21)	(8)
Reserve for unfunded lending commitments: Ending balance	1,997	1,659
Total allowance for credit losses	27,981	26,876
Allowance for credit losses: Individually evaluated	197
Allowance for credit losses: Collectively evaluated	27,784	26,876
Consumer [Member] | Non-Purchased Credit Impaired Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses: Charge-offs	(4,211)	(4,786)
Allowance for loan losses: Recoveries	804	914
Allowance for loan losses: Net provision for loan losses	$ 3,441	$ 3,677