Derivative Financial Instruments Effectiveness Testing (Details) (Interest rate swap [Member], USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Interest rate swap [Member]
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net	$ 0
Derivative Instruments, Loss Reclassified from Accumulated OCI into Income, Effective Portion	(2,400,000)	(4,100,000)	(4,200,000)
Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimated Net Amount to be Realized in the next 12 Months	$ (2,200,000)