Short-Term Borrowings - Balance, Weighted Average and Interest Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Short-term Debt [Line Items]
Balance	$ 140,163	$ 301,207	$ 488,383
Weighted Average Interest Rate	0.22%	1.76%	2.57%
Interest Expense	$ 1,603	$ 6,526	$ 11,304
REPOs
Short-term Debt [Line Items]
Balance	$ 65,163	$ 19,888	$ 18,383
Weighted Average Interest Rate	0.25%	0.74%	0.46%
Interest Expense	$ 169	$ 110	$ 222
FHLB advances
Short-term Debt [Line Items]
Balance	$ 75,000	$ 281,319	$ 470,000
Weighted Average Interest Rate	0.19%	1.84%	2.65%
Interest Expense	$ 1,434	$ 6,416	$ 11,082