Short and Long-Term Funding, FHLB Advances (Components of Short-term and Long-term Funding) (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Short-term Funding [Abstract]
Federal funds purchased	$ 175,135	$ 220,160
Securities sold under agreements to repurchase	90,536	106,620
Federal funds purchased and securities sold under agreements to repurchase	265,671	326,780
Bank Term Funding Program Funding	500,000	0
Total short-term funding	765,671	326,780
Long-term funding
Subordinated Debt	550,000	550,000
Other Long-term Debt and Capitalized Costs	(7,468)	(7,748)
Finance lease liability	361	383
Long-term Debt	536,055	541,269
TotalShortTermLongTermExcludingFHLB	1,301,726	868,049
Advance from Federal Home Loan Bank [Abstract]
Advance from Federal Home Loan Bank	138,000	740,000
Long-Term Federal Home Loan Bank Advances	1,209,862	1,209,907
Federal Home Loan Bank, Advances, Branch of FHLB Bank, Amount of Advances	1,333,411	1,940,194
Debt, Long-Term and Short-Term, Combined Amount	2,635,137	2,808,243
Fair Value Hedging [Member]
Long-term funding
Subordinated Debt	(6,838)	(1,366)
Advance from Federal Home Loan Bank [Abstract]
Advance from Federal Home Loan Bank	$ (14,451)	$ (9,713)