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, 2019	$ 237,516	$ 406	$ 78	$ 447,681	$ (1,013)	$ (210,942)		$ 1,306
Beginning balances, shares at Dec. 31, 2019		40,624	78,062,451
Vesting of restricted stock units	1		$ 1
Vesting of restricted stock units, shares			519,660
Stock-based compensation	3,323			3,323
Issuance of common stock under employee stock purchase plan	430			430
Issuance of common stock under employee stock purchase plan, shares			166,580
Common stock repurchased and retired under share repurchase program	$ (2,527)		$ (1)	(2,526)
Common stock repurchased and retired under share repurchase program, Shares	(836,904)		(836,904)
Exercise of SARs, shares			41,091
Net income (loss)	$ (13,478)					(13,645)		167
Foreign currency translation adjustments	308				337			(29)
Ending balances at Jun. 30, 2020	225,573	$ 406	$ 78	448,908	(676)	(224,587)		1,444
Ending balances, shares at Jun. 30, 2020		40,624	77,952,878
Beginning balances at Mar. 31, 2020	229,990	$ 406	$ 78	449,431	(907)	(217,917)	$ (2,502)	1,401
Beginning balances, shares at Mar. 31, 2020		40,624	78,525,184				836,904
Vesting of restricted stock units, shares			98,018
Stock-based compensation	1,549			1,549
Issuance of common stock under employee stock purchase plan	430			430
Issuance of common stock under employee stock purchase plan, shares			166,580
Common stock repurchased and retired under share repurchase program				(2,502)			$ 2,502
Common stock repurchased and retired under share repurchase program, Shares			(836,904)				(836,904)
Net income (loss)	(6,641)					(6,670)		29
Foreign currency translation adjustments	245				231			14
Ending balances at Jun. 30, 2020	225,573	$ 406	$ 78	448,908	(676)	(224,587)		1,444
Ending balances, shares at Jun. 30, 2020		40,624	77,952,878
Beginning balances at Dec. 31, 2020	209,415	$ 406	$ 78	451,327	1,021	(244,882)		1,465
Beginning balances, shares at Dec. 31, 2020		40,624	78,183,806
Vesting of restricted stock units	2		$ 2
Vesting of restricted stock units, shares			1,163,796
Stock-based compensation	3,113			3,113
Issuance of common stock under employee stock purchase plan	533			533
Issuance of common stock under employee stock purchase plan, shares			101,732
Common stock issued as payment for MPUs	352			352
Common stock issued as payment for MPUs, shares			47,404
Exercise of SARs, shares			154,215
Net income (loss)	(18,000)					(18,203)		203
Series A convertible preferred stock dividend		$ 29				(29)
Series A convertible preferred stock dividend, shares		(2,906)
Foreign currency translation adjustments	(1,590)				(1,559)			(31)
Ending balances at Jun. 30, 2021	193,825	$ 435	$ 80	455,325	(538)	(263,114)		1,637
Ending balances, shares at Jun. 30, 2021		43,530	79,650,953
Beginning balances at Mar. 31, 2021	199,169	$ 418	$ 79	453,379	(843)	(255,456)		1,592
Beginning balances, shares at Mar. 31, 2021		41,844	79,439,807
Vesting of restricted stock units, shares			4,000
Stock-based compensation	1,414		$ 1	1,413
Issuance of common stock under employee stock purchase plan	533			533
Issuance of common stock under employee stock purchase plan, shares			101,732
Exercise of SARs, shares			105,414
Net income (loss)	(7,609)					(7,641)		32
Series A convertible preferred stock dividend		$ 17				(17)
Series A convertible preferred stock dividend, shares		(1,686)
Foreign currency translation adjustments	318				305			13
Ending balances at Jun. 30, 2021	$ 193,825	$ 435	$ 80	$ 455,325	$ (538)	$ (263,114)		$ 1,637
Ending balances, shares at Jun. 30, 2021		43,530	79,650,953