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	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Effective Portion - Amount of Gain/(Loss) Recognized in OCI on Derivative	$ 11,995	$ 3,507
Effective Portion - Amount of Gain/(Loss) Reclassified from Accumulated OCI into Income	(9,307)	(9,251)
Ineffective Portion - Amount of Gain/ (Loss) Reclassified from Accumulated OCI into Income	0	0
Forward Starting Swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Effective Portion - Amount of Gain/(Loss) Recognized in OCI on Derivative	11,995	3,507
Effective Portion - Amount of Gain/(Loss) Reclassified from Accumulated OCI into Income	(9,307)	(9,251)
Ineffective Portion - Amount of Gain/ (Loss) Reclassified from Accumulated OCI into Income	$ 0	$ 0