Derivative and Other Fair Value Instruments - Summary of Effect of Cash Flow Hedges on the Accompanying Consolidated Statements of Operations and Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Effective Portion - Amount of Gain/(Loss) Recognized in OCI on Derivative	$ 6,439	$ (3,989)	$ (814)
Effective Portion - Amount of Gain/(Loss) Reclassified from Accumulated OCI into Income	(18,858)	(41,758)	(18,244)
Ineffective Portion - Amount of Gain/ (Loss) Reclassified from Accumulated OCI into Income		(74)	(3,033)
Forward Starting Swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Effective Portion - Amount of Gain/(Loss) Recognized in OCI on Derivative	6,439	(3,989)	(814)
Effective Portion - Amount of Gain/(Loss) Reclassified from Accumulated OCI into Income	$ (18,858)	(41,758)	(18,244)
Ineffective Portion - Amount of Gain/ (Loss) Reclassified from Accumulated OCI into Income		$ (74)	$ (3,033)