Derivative Instruments and Hedging Activities (Details) - Other Derivative Instruments - Other Derivative Instruments - USD ($) $ in Thousands		Sep. 30, 2015	Dec. 31, 2014
Derivative [Line Items]
Gross notional amount outstanding		$ 685,270	$ 527,893
Derivative asset fair value		13,367	7,852
Derivative liability fair value		(13,367)	(7,852)
Fair value of assets needed to settle derivative transactions	[1]	$ 13,764	$ 8,130

[1] This amount represents the fair value if credit risk related contingent features were triggered.