Condensed Consolidated Statements of Changes in Equity - 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, 2016	$ 281,868	$ 364	$ 71	$ 386,920	$ (1,089)	$ (104,949)	$ (96)	$ 647
Beginning balances, shares at Dec. 31, 2016		36,466	71,111,863				29,990
Vesting of restricted stock units	1		$ 1
Vesting of restricted stock units, shares			554,469
Stock-based compensation	1,498			1,498
Exercise of SARs, shares			29,470
Net income (loss)	(3,301)					(3,343)		42
Foreign currency translation adjustments	196				202			(6)
Ending balances at Mar. 31, 2017	280,262	$ 364	$ 72	388,418	(887)	(108,292)	$ (96)	683
Ending balances, shares at Mar. 31, 2017		36,466	71,695,802				29,990
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