Condensed Consolidated Statements of Changes in Equity (Unaudited) - USD ($) $ in Thousands	Total	Series A Convertible Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Deficit [Member]	Treasury Stock [Member]	Noncontrolling Interests [Member]
Beginning balances at Dec. 31, 2017	$ 246,396	$ 376	$ 74	$ 411,298	$ 256	$ (166,245)	$ (96)	$ 733
Beginning balances, shares at Dec. 31, 2017		37,544	74,436,579				29,990
Vesting of restricted stock units	1		$ 1
Vesting of restricted stock units, shares			459,039
Stock-based compensation	1,741			1,741
Common stock issued as payment for MPUs	827			827
Common stock issued as payment for MPUs, shares			81,277
Exercise of SARs, shares			33,895
Net income (loss)	(10,063)					(10,086)		23
Foreign currency translation adjustments	420				418			2
Ending balances at Mar. 31, 2018	239,322	$ 376	$ 75	413,866	674	(176,331)	$ (96)	758
Ending balances, shares at Mar. 31, 2018		37,544	75,010,790				29,990
Beginning balances at Dec. 31, 2018	257,858	$ 394	$ 79	449,343	(381)	(192,507)	$ (96)	1,026
Beginning balances, shares at Dec. 31, 2018		39,442	79,008,243				29,990
Vesting of restricted stock units	1		$ 1
Vesting of restricted stock units, shares			496,336
Stock-based compensation	2,395			2,395
Common stock issued as payment for MPUs	502			502
Common stock issued as payment for MPUs, shares			60,885
Exercise of SARs, shares			3,032
Net income (loss)	(5,396)					(5,490)		94
Foreign currency translation adjustments	(515)				(506)			(9)
Ending balances at Mar. 31, 2019	$ 254,845	$ 394	$ 80	$ 452,240	$ (887)	$ (197,997)	$ (96)	$ 1,111
Ending balances, shares at Mar. 31, 2019		39,442	79,568,496				29,990