Accumulated Other Comprehensive Loss (Amounts Reclassified from AOCI) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Settlement Loss and Mark-to-Market Gain on Interest Rate Protection Agreements	$ (11,546)	$ 0	$ 52
Interest Expense	67,424	72,178	73,558
Loss from Retirement of Debt	0	(655)	(6,637)
Total	(33,162)	(73,904)	(79,914)
Reclassification Out Of Accumulated Other Comprehensive Income | Interest Rate Protection Agreements
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total	19,043	5,349	3,527
Interest Rate Swap | Reclassification Out Of Accumulated Other Comprehensive Income | Interest Rate Protection Agreements
Accumulated Other Comprehensive Income (Loss) [Line Items]
Settlement Loss and Mark-to-Market Gain on Interest Rate Protection Agreements	12,990	0	0
Interest Expense	5,529	3,991	0
Interest Rate Contract | Reclassification Out Of Accumulated Other Comprehensive Income | Interest Rate Protection Agreements
Accumulated Other Comprehensive Income (Loss) [Line Items]
Interest Expense	524	1,358	2,411
Loss from Retirement of Debt	$ 0	$ 0	$ 1,116