Borrowed Funds - Schedule of Short-Term Borrowings (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Total short-term borrowings	$ 1,147,958	$ 1,093,280
Loss on extinguishment of debt	12,036	31,995	$ 0
Short-term borrowings
Debt Instrument [Line Items]
FHLB advances	1,000,000	940,000
Securities sold under agreements to repurchase	147,958	153,280
Total short-term borrowings	$ 1,147,958	$ 1,093,280