Short and Long-term Funding, Composition (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Short-term Debt [Line Items]
Federal funds purchased	$ 120	$ 7,070
Securities sold under agreements to repurchase	319,412	185,901
Federal funds purchased and securities sold under agreements to repurchase	319,532	192,971
Commercial paper	34,730	59,346
Total short-term funding	354,262	252,317
Debt Instrument [Line Items]
Corporation subordinated notes, at par, due 2025	250,000	250,000
Other Long-term Debt and Capitalized Costs	(839)	(1,663)
Finance Lease, Liability	163	1,128
Other Long-term Debt	1,870,371	2,182,188
Advances from Federal Home Loan Banks [Abstract]
Federal Home Loan Bank, Advances, Branch of FHLB Bank, Amount of Advances	1,621,047	1,632,723
Debt, Long-term and Short-term, Combined Amount [Abstract]
Debt, Long-term and Short-term, Combined Amount, Total	2,224,633	2,434,505
Bank senior notes, at par, due 2021
Debt Instrument [Line Items]
Senior Notes	$ 0	$ 300,000