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		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Derivative [Line Items]
Unrealized Gain (Loss)	$ 27,119	$ 12,413	$ 39,386	$ 2,414
Realized Loss	(149)	(10,414)	(269)	(11,165)
Total Gain (Loss)	26,970	1,999	39,117	(8,751)
Contingent redemption features - Series A Preferred Stock
Derivative [Line Items]
Unrealized Gain (Loss)	27,219	0	39,442	0
Total Gain (Loss)	27,219	0		0
Cross currency and interest rate swaps
Derivative [Line Items]
Unrealized Gain (Loss)	(145)	12,463	(127)	2,465
Realized Loss	(149)	(10,365)	(269)	(11,069)
Total Gain (Loss)	(294)	2,098	(396)	(8,604)
Interest rate swaps
Derivative [Line Items]
Unrealized Gain (Loss)	45	(50)	71	(51)
Realized Loss	0	(49)	0	(96)
Total Gain (Loss)	$ 45	$ (99)	$ 71	$ (147)