Derivative Instruments - Derivative Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Not designated as hedging instruments:
Derivative financial instruments
Derivative assets	$ 9,311	$ 5,977
Derivative liabilities	4,565	3,503
Designated as hedging instruments:
Derivative financial instruments
Derivative liabilities	1,385	2,536
Other Assets | Not designated as hedging instruments: | Interest rate contracts
Derivative financial instruments
Derivative assets	3,636	3,171
Other Assets | Not designated as hedging instruments: | Interest rate lock commitments
Derivative financial instruments
Derivative assets	4,940	2,756
Other Assets | Not designated as hedging instruments: | Forward commitments
Derivative financial instruments
Derivative assets	735	50
Other Liabilities | Not designated as hedging instruments: | Interest rate contracts
Derivative financial instruments
Derivative liabilities	3,636	3,171
Other Liabilities | Not designated as hedging instruments: | Interest rate lock commitments
Derivative financial instruments
Derivative liabilities	4	4
Other Liabilities | Not designated as hedging instruments: | Forward commitments
Derivative financial instruments
Derivative liabilities	925	328
Other Liabilities | Designated as hedging instruments: | Interest rate swaps
Derivative financial instruments
Derivative liabilities	$ 1,385	$ 2,536