Derivative Instruments and Hedging Activities - Value of Derivative Assets and Derivative Liabilities (Details) - Not Designated as Hedging Instruments - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Other Assets
Derivatives not Designated as Hedging Instruments
Fair value, Derivatives (included in Other Assets)	$ 4,669	$ 3,074
Other Assets | Interest rate swaps
Derivatives not Designated as Hedging Instruments
Fair value, Derivatives (included in Other Assets)	4,669	3,074
Notional amount, Derivatives (included in Other Assets)	253,580	263,841
Net collateral received/posted, Derivatives	2,011	0
Other Assets | Interest rate lock commitments
Derivatives not Designated as Hedging Instruments
Fair value, Derivatives (included in Other Assets)	271	226
Notional amount, Derivatives (included in Other Assets)	9,710	6,860
Other Assets | Forward sale contracts
Derivatives not Designated as Hedging Instruments
Fair value, Derivatives (included in Other Assets)	0	0
Notional amount, Derivatives (included in Other Assets)	0	0
Other Liabilities
Derivatives not Designated as Hedging Instruments
Fair value, Derivatives (included in Other Liabilities)	4,765	3,055
Other Liabilities | Interest rate swaps
Derivatives not Designated as Hedging Instruments
Fair value, Derivatives (included in Other Liabilities)	4,765	3,055
Notional amount, Derivatives (included in Other Liabilities)	253,580	263,841
Net collateral received/posted, Derivatives	0	1,448
Other Liabilities | Interest rate lock commitments
Derivatives not Designated as Hedging Instruments
Fair value, Derivatives (included in Other Liabilities)	0	0
Notional amount, Derivatives (included in Other Liabilities)	0	0
Other Liabilities | Forward sale contracts
Derivatives not Designated as Hedging Instruments
Fair value, Derivatives (included in Other Liabilities)	24	5
Notional amount, Derivatives (included in Other Liabilities)	$ 9,165	$ 6,580