Accounting for Derivatives (Details 3) - Derivatives designated as cash flow hedges - Interest rate hedges - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Effect of derivative instruments on results of operations
Gain (Loss) Recognized in Other Comprehensive Income (Loss) on Derivatives	$ 255	$ (2,174)	$ (5,998)	$ (3,129)
Interest Expense
Effect of derivative instruments on results of operations
Gain (Loss) Reclassified from Accumulated Other Comprehensive Income (Loss) into Income (Loss)	$ (1,891)	$ (1,015)	$ (3,416)	$ (2,015)