Derivative Instruments - Derivative Financial Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Derivative financial instruments
Derivative assets	$ 181	$ 0
Not designated as hedging instruments:
Derivative financial instruments
Derivative assets	8,939	5,977
Derivative liabilities	5,444	3,503
Designated as hedging instruments:
Derivative financial instruments
Derivative liabilities	1,047	2,536
Other Assets | Not designated as hedging instruments: | Interest rate contracts
Derivative financial instruments
Derivative assets	4,142	3,171
Other Assets | Not designated as hedging instruments: | Interest rate lock commitments
Derivative financial instruments
Derivative assets	4,699	2,756
Other Assets | Not designated as hedging instruments: | Forward commitments
Derivative financial instruments
Derivative assets	98	50
Other Assets | Designated as hedging instruments: | Interest rate swaps
Derivative financial instruments
Derivative assets	181	0
Other Liabilities | Not designated as hedging instruments: | Interest rate contracts
Derivative financial instruments
Derivative liabilities	4,142	3,171
Other Liabilities | Not designated as hedging instruments: | Interest rate lock commitments
Derivative financial instruments
Derivative liabilities	1	4
Other Liabilities | Not designated as hedging instruments: | Forward commitments
Derivative financial instruments
Derivative liabilities	1,301	328
Other Liabilities | Designated as hedging instruments: | Interest rate swaps
Derivative financial instruments
Derivative liabilities	$ 1,047	$ 2,536