Short-Term Borrowings and Long-Term Debt Short Term (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Short-term Debt [Line Items]
Short-term borrowings	$ 630,066	$ 883,241	$ 754,777
Maximum borrowing capacity	1,800,000
Collateralized borrowings availability at discount window	324,300	334,300
Federal funds purchased
Short-term Debt [Line Items]
Short-term borrowings	0	0	0
Maximum borrowing capacity	200,000	274,998	525,000
Short-term FHLB advances
Short-term Debt [Line Items]
Short-term borrowings	0	500,000	385,000
Maximum borrowing capacity	980,000	825,000	385,000
Customer funding
Short-term Debt [Line Items]
Short-term borrowings	630,066	383,241	369,777
Maximum borrowing capacity	$ 630,066	$ 404,207	$ 547,678