Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Net revenues	$ 163,266	$ 163,260	$ 150,329	$ 104,528	$ 128,031	$ 161,245	$ 107,267	$ 91,039	$ 581,383	$ 487,582	$ 695,802
Gross profit (loss)	23,483	21,141	18,367	(825)	17,604	40,184	5,658	(16,930)	$ 62,166	$ 46,516	$ (233,774)
Net income (loss)	$ 50,580	$ 2,290	$ (6,403)	$ (16,415)	$ (54,413)	$ 11,462	$ (10,671)	$ (27,823)
Basic earnings (loss) per common share (in dollars per share)	$ 0.34	$ 0.02	$ (0.04)	$ (0.11)	$ (0.46)	$ 0.10	$ (0.10)	$ (0.26)	$ 0.20	$ (0.73)	$ (3.58)
Diluted earnings (loss) per common share (in dollars per share)	$ 0.34	$ 0.02	$ (0.04)	$ (0.11)	$ (0.46)	$ 0.10	$ (0.10)	$ (0.26)	$ 0.20	$ (0.73)	$ (3.58)
Quarterly Financial Information [Line Items]
Income tax benefit due to U.S. tax law changes	$ 51,600
Goodwill impairment									$ 0	$ 45,107	$ 16,399
Robotics [Member]
Quarterly Financial Information [Line Items]
Goodwill impairment	$ 45,100									$ 45,100