Derivative Instruments and Hedging Activities - Schedule of Gross Amounts of Derivative Assets and Derivative Liabilities (Details) - Not Designated as Hedging Instruments - USD ($) $ in Thousands		Sep. 30, 2017	Dec. 31, 2016
Other Assets
Derivatives (included in Other Assets)
Gross amounts recognized		$ 6,124	$ 8,590
Gross amounts offset		(1,310)	(1,630)
Net amounts presented in the Consolidated Balance Sheets		4,814	6,960
Gross amounts not offset	[1]	0	0
Net Amount		4,814	6,960
Other Liabilities
Derivatives (included in Other Liabilities)
Gross amounts recognized		6,096	8,588
Gross amounts offset		(1,310)	(1,630)
Net amounts presented in the Consolidated Balance Sheets		4,786	6,958
Gross amounts not offset	[1]	(3,505)	(14,340)
Net Amount		$ 1,281	$ (7,382)

[1] Amounts represent posted collateral.