CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating activities
Net income (loss)	$ (30,768)	$ 1,720	$ (95,695)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization	32,389	34,020	35,312
Release of contingent consideration		(2,001)
Stock-based compensation expense	12,914	15,721	13,459
Impairments	7,719		38,559
Restructuring and other charges	35,380	174	60,043
Gain on sale of property, plant and equipment	(587)	(1,511)	(6,198)
Deferred income taxes	4,950	598	(4,091)
Changes in operating assets and liabilities:
Trade receivables, net	(9,522)	10,783	17,988
Unbilled receivables	216	(57,032)	(29,843)
Inventories, net	(28,290)	(14,054)	49,926
Prepaids and other assets	(24,930)	10,980	(15,084)
Accounts payable and accrued expenses	(20,387)	15,343	(18,755)
Other, net	(172)	(63)	(118)
Net cash provided by (used in) operating activities	(21,088)	14,678	45,503
Investing activities
Purchase of property, plant and equipment	(11,943)	(11,501)	(32,061)
Proceeds from sale of equipment	6,315	3,030	16,888
Net cash used in investing activities	(5,628)	(8,471)	(15,173)
Financing activities
Proceeds from exercise of stock options		2,181	1,616
ABL Credit Facility issuance costs			(815)
Repurchase of common shares	(25,000)	(26,570)	(100,000)
Other	(183)	(183)
Net cash used in financing activities	(25,183)	(24,572)	(99,199)
Effect of exchange rate changes on cash activities	(1,092)	(789)	(6,211)
Decrease in cash and cash equivalents	(52,991)	(19,154)	(75,080)
Cash and cash equivalents at beginning of year	398,946	418,100	493,180
Cash and cash equivalents at end of year	$ 345,955	$ 398,946	$ 418,100