CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Preferred Stock [Member]	Common Stock [Member]	Paid-In Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Non-controlling Interest [Member]	Total
Beginning balance at Dec. 31, 2018		$ 451	$ 411,423	$ (84,030)	$ (166,206)	$ (337)	$ 14,930	$ 176,231
Beginning balance, shares at Dec. 31, 2018	1	45,100,771
Beginning balance, Treasury Stock, shares at Dec. 31, 2018						(28,308)
Share-based compensation			2,968					2,968
Net (loss) income					(11,966)		2,088	(9,878)
Distribution to noncontrolling interest							(600)	(600)
Shares withheld						$ (309)		(309)
Shares withheld, shares						(54,529)
Cemblend exchangeable shares		$ 13	(13)
Cemblend exchangeable shares, shares	(1)	1,326,935
Proceeds from the issuance of ESPP		$ 2	675					677
Proceeds from the issuance of ESPP, shares		156,486
Currency translation adjustment				1,537				1,537
Ending balance at Mar. 31, 2019		$ 468	415,051	(82,493)	(178,172)	$ (646)	16,418	170,626
Ending balance, shares at Mar. 31, 2019		46,752,755
Ending balance, Treasury Stock, shares at Mar. 31, 2019						(82,837)
Beginning balance at Dec. 31, 2018		$ 451	411,423	(84,030)	(166,206)	$ (337)	14,930	176,231
Beginning balance, shares at Dec. 31, 2018	1	45,100,771
Beginning balance, Treasury Stock, shares at Dec. 31, 2018						(28,308)
Net (loss) income								(29,446)
Vesting of restricted stock		$ 2	(2)
Vesting of restricted stock, shares		168,563
Currency translation adjustment								3,022
Ending balance at Jun. 30, 2019		$ 468	418,365	(81,008)	(200,473)	$ (646)	19,151	155,857
Ending balance, shares at Jun. 30, 2019		46,752,755
Ending balance, Treasury Stock, shares at Jun. 30, 2019						(82,837)
Beginning balance at Mar. 31, 2019		$ 468	415,051	(82,493)	(178,172)	$ (646)	16,418	170,626
Beginning balance, shares at Mar. 31, 2019		46,752,755
Beginning balance, Treasury Stock, shares at Mar. 31, 2019						(82,837)
Share-based compensation			3,314					3,314
Net (loss) income					(22,301)		2,733	(19,568)
Currency translation adjustment				1,485				1,485
Ending balance at Jun. 30, 2019		$ 468	418,365	(81,008)	(200,473)	$ (646)	19,151	155,857
Ending balance, shares at Jun. 30, 2019		46,752,755
Ending balance, Treasury Stock, shares at Jun. 30, 2019						(82,837)
Beginning balance at Dec. 31, 2019		$ 469	424,633	(80,811)	(199,029)	$ (652)	18,935	$ 163,545
Beginning balance, shares at Dec. 31, 2019		46,905,782
Beginning balance, Treasury Stock, shares at Dec. 31, 2019						(92,665)		(92,665)
Share-based compensation			2,950					$ 2,950
Net (loss) income					(51,549)		2,642	(48,907)
Distribution to noncontrolling interest							(3,050)	(3,050)
Vesting of restricted stock		$ 5	(5)
Vesting of restricted stock, shares		481,996
Shares withheld						$ (151)		(151)
Shares withheld, shares						(137,855)
Currency translation adjustment				(5,249)				(5,249)
Ending balance at Mar. 31, 2020		$ 474	427,578	(86,060)	(250,578)	$ (803)	18,527	109,138
Ending balance, shares at Mar. 31, 2020		47,387,778
Ending balance, Treasury Stock, shares at Mar. 31, 2020						(230,520)
Beginning balance at Dec. 31, 2019		$ 469	424,633	(80,811)	(199,029)	$ (652)	18,935	$ 163,545
Beginning balance, shares at Dec. 31, 2019		46,905,782
Beginning balance, Treasury Stock, shares at Dec. 31, 2019						(92,665)		(92,665)
Net (loss) income								$ (57,799)
Currency translation adjustment								(3,657)
Ending balance at Jun. 30, 2020		$ 474	429,300	(84,468)	(259,335)	$ (805)	18,392	$ 103,558
Ending balance, shares at Jun. 30, 2020		47,414,602
Ending balance, Treasury Stock, shares at Jun. 30, 2020						(235,013)		(235,013)
Beginning balance at Mar. 31, 2020		$ 474	427,578	(86,060)	(250,578)	$ (803)	18,527	$ 109,138
Beginning balance, shares at Mar. 31, 2020		47,387,778
Beginning balance, Treasury Stock, shares at Mar. 31, 2020						(230,520)
Share-based compensation			1,722					1,722
Net (loss) income					(8,757)		(135)	(8,892)
Exercise of stock options, shares		13,500
Vesting of restricted stock, shares		13,324
Shares withheld						$ (2)		(2)
Shares withheld, shares						(4,493)
Currency translation adjustment				1,592				1,592
Ending balance at Jun. 30, 2020		$ 474	$ 429,300	$ (84,468)	$ (259,335)	$ (805)	$ 18,392	$ 103,558
Ending balance, shares at Jun. 30, 2020		47,414,602
Ending balance, Treasury Stock, shares at Jun. 30, 2020						(235,013)		(235,013)