CONDENSED CONSOLIDATED STATEMENTS OF EQUITY - 3 months ended Mar. 31, 2019 - USD ($) $ in Thousands	Total	Additional Paid-In Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income [Member]	Noncontrolling Interest [Member]	Preferred Class A [Member] Series A Convertible Preferred Stock [Member]	Common Class A [Member] Common Stock [Member]	Common Class B [Member]	Common Class B [Member] Common Stock [Member]
BALANCE at Dec. 31, 2018	$ 229,321	$ 2,003,518	$ (1,578,076)	$ (216,650)	$ 301	$ 0	$ 20,228		$ 0
BALANCE (in shares) at Dec. 31, 2018						1
BALANCE (in shares) at Dec. 31, 2018							252,853,554	0	0
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Stock-based compensation	1,003	1,003
Shares issuance, stock-based compensation (in shares)							426,421
Share issuance, stock-based compensation	0	(34)					$ 34
Adjustments Related to Tax Withholding for Share-based Compensation	299	299
Net income / (loss)	11,751		11,758		(7)
Unrealized (loss) / gain on derivative instruments (Note 12)	(3,331)			(3,331)
Currency translation adjustment	(15,843)			(15,980)	137
Currency translation adjustment	(15,843)
BALANCE at Mar. 31, 2019	$ 222,602	$ 2,004,188	$ (1,566,318)	$ (235,961)	$ 431	$ 0	$ 20,262		$ 0
BALANCE (in shares) at Mar. 31, 2019						1
BALANCE (in shares) at Mar. 31, 2019							253,279,975	0	0