Derivative Instruments - Realized and Unrealized Gain (Loss) on Derivatives Not Designated as Hedging Instruments (Details) - Derivatives not designated as hedging instruments: - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Derivative [Line Items]
Unrealized (Loss) Gain	$ (9,172)	$ 12,267
Realized Loss	(10,168)	(120)
Total (Loss) Gain	(19,340)	12,147
Contingent redemption features - Series A Preferred Stock
Derivative [Line Items]
Unrealized (Loss) Gain	(13,533)	12,223
Total (Loss) Gain	(13,533)	12,223
Cross currency and interest rate swaps
Derivative [Line Items]
Unrealized (Loss) Gain	4,305	18
Realized Loss	(10,168)	(120)
Total (Loss) Gain	(5,863)	(102)
Interest rate swaps
Derivative [Line Items]
Unrealized (Loss) Gain	56	26
Total (Loss) Gain	$ 56	$ 26