Cumulative Other Comprehensive Loss - Schedule of Reclassifications Out of Cumulative Other Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reclassifications out of cumulative other comprehensive income (Loss)
Interest expense	$ 52,183	$ 84,329	$ 107,316
Interest and other income	26,380	10,331	$ 5,989
Amounts reclassified from cumulative other comprehensive loss to net income	(49)
Amounts Reclassified from Cumulative Other Comprehensive Loss to Net Income
Reclassifications out of cumulative other comprehensive income (Loss)
Amounts reclassified from cumulative other comprehensive loss to net income	49	4,033
Amounts Reclassified from Cumulative Other Comprehensive Loss to Net Income | Interest rate swap contracts
Reclassifications out of cumulative other comprehensive income (Loss)
Interest expense	0	3,792
Interest and other income	0	241
Amounts Reclassified from Cumulative Other Comprehensive Loss to Net Income | Interest rate cap contract
Reclassifications out of cumulative other comprehensive income (Loss)
Interest expense	$ 49	$ 0