Derivative and Hedging Activities - Schedule of Derivative Instruments (Details) (Designated as Hedging Instrument, Swap, Foreign currency swaps, USD $) In Thousands, unless otherwise specified	Dec. 31, 2014 derivative	Dec. 31, 2013 derivative
Derivative [Line Items]
Number of Instruments	15	7
Notional Amount	$ 241,908	$ 35,597
EUR-USD Forwards
Derivative [Line Items]
Number of Instruments	10	0
Notional Amount	107,623	0
GBP-USD Forwards
Derivative [Line Items]
Number of Instruments	5	7
Notional Amount	$ 134,285	$ 35,597