Short-Term Borrowings - Average Balances and Cost of Funds (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Short-term Debt [Line Items]
Average Balances	$ 155,735	$ 217,547	$ 356,929
Cost of Funds	2.10%	1.22%	0.45%
Federal Home Loan Bank short-term advances
Short-term Debt [Line Items]
Average Balances	$ 147,749	$ 208,332	$ 344,724
Cost of Funds	2.21%	1.27%	0.46%
Securities sold under agreements to repurchase
Short-term Debt [Line Items]
Average Balances	$ 7,986	$ 9,215	$ 12,205
Cost of Funds	0.17%	0.17%	0.20%