Derivative Instruments and Hedging Activities - Balance Sheet Disclosures (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Interest rate swaps
Derivative [Line Items]
Other Assets	$ 0	$ 0
Other Liabilities	22,091	22,907
Derivatives designated as hedging instruments
Derivative [Line Items]
Other Assets	0	0
Other Liabilities	1,655	374
Notional Amount	289,474	339,536
Derivatives designated as hedging instruments | Cash flow hedge interest rate swaps | Interest rate swaps
Derivative [Line Items]
Other Assets	0	0
Other Liabilities	1,317	27
Notional Amount	282,000	332,000
Derivatives designated as hedging instruments | Fair value hedge interest rate swaps | Interest rate swaps
Derivative [Line Items]
Other Assets	0	0
Other Liabilities	338	347
Notional Amount	7,474	7,536
Derivatives not designated as hedging instruments
Derivative [Line Items]
Other Assets	79,252	48,979
Other Liabilities	21,021	23,307
Notional Amount	3,436,528	3,495,825
Derivatives not designated as hedging instruments | Interest rate swaps
Derivative [Line Items]
Other Assets	78,782	48,642
Other Liabilities	20,436	22,533
Notional Amount	3,332,581	3,390,578
Derivatives not designated as hedging instruments | Mortgage banking derivatives
Derivative [Line Items]
Other Assets	470	337
Other Liabilities	585	774
Notional Amount	$ 103,947	$ 105,247