Cumulative Other Comprehensive Loss - Schedule of Reclassifications Out of Cumulative Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Reclassifications out of cumulative other comprehensive income (Loss)
Interest expense	$ 21,300	$ 27,973	$ 43,647	$ 57,815
Amounts Reclassified from Cumulative Other Comprehensive Loss to Net Income | Interest rate swap contracts
Reclassifications out of cumulative other comprehensive income (Loss)
Interest expense	$ 1,106		$ 2,224