CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Operating activities
Net income (loss)	$ (10,421)	$ 110
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	17,242	22,713
Stock-based compensation expense	7,585	6,783
Gain on sale of equipment	(5,099)	(88)
Deferred income taxes	578	(1,486)
Changes in operating assets and liabilities:
Trade receivables, net	7,007	(4,823)
Inventories	22,731	29,246
Prepaids and other assets	(3,117)	4,471
Accounts payable and accrued expenses	(13,374)	(18,226)
Other, net	334	0
Net cash provided by operating activities	23,466	38,700
Investing activities
Purchase of property, plant and equipment	(19,605)	(12,936)
Proceeds from sale of equipment	10,517	610
Acquisition of business, net of cash acquired	0	(21,289)
Net cash used in investing activities	(9,088)	(33,615)
Financing activities
Repurchase of common stock	(9,830)	0
ABL Credit Facility issuance costs	(815)	0
Proceeds from exercise of stock options	642	403
Net cash provided by (used in) financing activities	(10,003)	403
Effect of exchange rate changes on cash activities	(4,133)	8,002
Increase in cash and cash equivalents	242	13,490
Cash and cash equivalents at beginning of period	493,180	423,497
Cash and cash equivalents at end of period	$ 493,422	$ 436,987