Unaudited Condensed Consolidated Statements of Stockholders' Deficit - 9 months ended Sep. 30, 2018 - USD ($) shares in Thousands, $ in Thousands	Total	5.75% Convertible Notes	1.50% Convertible Notes	Common Stock	Common Stock 5.75% Convertible Notes	Additional Paid-in Capital	Additional Paid-in Capital 5.75% Convertible Notes	Additional Paid-in Capital 1.50% Convertible Notes	Accumulated Losses	AOCI Attributable to Parent	Treasury Stock	Noncontrolling Interest
Beginning Balance at Dec. 31, 2017	$ (50,976)			$ 90		$ 1,044,518			$ (223,718)	$ (51,280)	$ (844,030)	$ 23,444
Beginning Balance (in shares) at Dec. 31, 2017				90,159
Shares issued on vesting of restricted stock	1			$ 1
Shares issued on vesting of restricted stock (in shares)				317
Shares issued on conversion of 5.75% Convertible Notes		$ 12,694			$ 11		$ 12,683
Shares issued on conversion of 5.75% Convertible Notes (in shares)					11,035
Shares issued on payment of interest of 5.75% Convertible Notes		$ 3,067			$ 6		$ 3,061
Shares issued on payment of interest of 5.75% Convertible Notes (in shares)					6,254
Write-off of equity component of 1.50% Convertible Notes			$ (23,250)					$ (23,250)
Elimination of non-controlling interest related to the acquisition of additional interest in Hydraulic joint venture						2,097						(2,097)
Shares repurchased on vesting of restricted stock and exercise of stock options	(147)										(147)
Compensation expense in connection with restricted stock and stock options	(108)					(108)
Payments from non-controlling interest holders, net of imputed interest	195											195
Change in redemption value of redeemable non-controlling interest	1,498								1,498
Net (loss) income	(22,811)								(31,446)			8,635
Tax benefit related to amortization of convertible notes' discount	35					35
Foreign currency translation	(3,538)					(29)				(3,509)
Distributions to joint ventures	(9,285)											(9,285)
Ending Balance at Sep. 30, 2018	(74,909)			$ 108		$ 1,039,007			(240,303)	(51,612)	$ (844,177)	22,068
Ending Balance (in shares) at Sep. 30, 2018				107,765
Cumulative effect of accounting change for adoption | ASC 606	$ 17,716								16,540			$ 1,176
Cumulative effect of accounting change for adoption | ASU 2016-01									$ (3,177)	$ 3,177