Derivative and Other Fair Value Instruments - Summary of Effect of Fair Value 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]
Amount of Gain/(Loss) Recognized in Income on Derivative	$ (3,454)	$ (1,798)	$ 2,058
Amount of Gain/(Loss) Recognized in Income on Hedged Item	3,454	1,798	(2,058)
Interest Rate Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain/(Loss) Recognized in Income on Derivative	(3,454)	(1,798)	2,058
Amount of Gain/(Loss) Recognized in Income on Hedged Item	$ 3,454	$ 1,798	$ (2,058)