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, 2019	Mar. 31, 2018
Derivative [Line Items]
Unrealized Gain (Loss)	$ 6,576	$ (9,172)
Realized Loss	(1,393)	(10,168)
Total Gain (Loss)	5,183	(19,340)
Contingent redemption features - Series A Preferred Stock
Derivative [Line Items]
Unrealized Gain (Loss)	0	(13,533)
Total Gain (Loss)	0	(13,533)
Cross currency and interest rate swaps
Derivative [Line Items]
Unrealized Gain (Loss)	6,576	4,305
Realized Loss	(1,393)	(10,168)
Total Gain (Loss)	5,183	(5,863)
Interest rate swaps
Derivative [Line Items]
Unrealized Gain (Loss)	0	56
Total Gain (Loss)	$ 0	$ 56