Short-Term Borrowings (Short-Term Borrowings) (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
Short-Term Debt [Line Items]
Amount outstanding at period end	$ 1,629,538		$ 1,629,538		$ 1,871,271
Federal Funds Purchased [Member]
Short-Term Debt [Line Items]
Amount outstanding at period end	$ 400		$ 400		$ 1,850
Weighted-average interest at period end	4.65%		4.65%		3.90%
Average amount outstanding during period	$ 1,287	$ 2,735	$ 4,829	$ 2,562
Maximum amount at any month end during period	$ 400	$ 2,350	$ 1,850	$ 2,350
Weighted-average interest rate during period	5.17%	0.82%	5.12%	0.57%
Securities Sold under Agreements to Repurchase [Member]
Short-Term Debt [Line Items]
Amount outstanding at period end	$ 529,138		$ 529,138		$ 444,421
Weighted-average interest at period end	1.25%		1.25%		0.53%
Average amount outstanding during period	$ 497,940	$ 523,041	$ 472,001	$ 555,096
Maximum amount at any month end during period	$ 625,773	$ 518,014	$ 625,773	$ 640,592
Weighted-average interest rate during period	1.38%	0.08%	1.05%	0.07%
FHLB Borrowings [Member]
Short-Term Debt [Line Items]
Amount outstanding at period end	$ 1,100,000		$ 1,100,000		$ 1,425,000
Weighted-average interest at period end	5.13%		5.13%		4.70%
Average amount outstanding during period	$ 1,887,363	$ 698,407	$ 1,766,575	$ 898,099
Maximum amount at any month end during period	$ 3,000,000	$ 1,100,000	$ 3,100,000	$ 1,100,000
Weighted-average interest rate during period	5.10%	0.49%	4.93%	0.49%