Derivative Instruments and Hedging Activities - Balance Sheet Disclosures (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Interest rate swaps
Derivative [Line Items]
Other Assets	$ 0	$ 0
Other Liabilities	32,833	22,907
Derivatives designated as hedging instruments
Derivative [Line Items]
Other Assets	0	0
Other Liabilities	2,496	374
Notional Amount	262,411	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	2,159	27
Notional Amount	255,000	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	337	347
Notional Amount	7,411	7,536
Derivatives not designated as hedging instruments
Derivative [Line Items]
Other Assets	140,496	48,979
Other Liabilities	31,006	23,307
Notional Amount	3,609,803	3,495,825
Derivatives not designated as hedging instruments | Interest rate swaps
Derivative [Line Items]
Other Assets	139,893	48,642
Other Liabilities	30,337	22,533
Notional Amount	3,469,497	3,390,578
Derivatives not designated as hedging instruments | Mortgage banking derivatives
Derivative [Line Items]
Other Assets	603	337
Other Liabilities	669	774
Notional Amount	$ 140,306	$ 105,247