Derivative Financial Instruments - Effect of Derivative Financial Instruments on Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Designated as Hedging Instrument | Cash Flow Hedging | Interest Expense
Derivative [Line Items]
Amount of Gain (Loss) Reclassified from Other Comprehensive Income into Income (Effective Portion)	$ (362)	$ (356)	$ (1,074)	$ (1,051)
Interest rate contracts | Not Designated as Hedging Instrument | Other income
Derivative [Line Items]
Amount of Gain (Loss) Recognized Income on Derivative	(194)	43	(139)	31
Interest rate contracts | Designated as Hedging Instrument | Cash Flow Hedging
Derivative [Line Items]
Amount of Gain (Loss) Recognized in Other Comprehensive Income on Derivative (Effective Portion)	$ (1,791)	$ 28	$ (2,260)	$ (2,530)