CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Operating activities
Net income	$ 94	$ 36,769
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	9,832	7,775
Stock-based compensation expense	3,216	3,192
Loss (gain) on sale of equipment	0	(13)
Deferred income taxes	(1,121)	(962)
Changes in operating assets and liabilities:
Trade receivables, net	7,044	(8,942)
Inventories, net	11,591	1,899
Prepaids and other assets	3,051	8,050
Excess tax benefits of stock options and awards	0	(11)
Accounts payable and accrued expenses	(22,231)	4,766
Net cash provided by operating activities	11,476	52,523
Investing activities
Purchase of property, plant and equipment	(4,847)	(7,732)
Proceeds from sale of equipment	439	76
Acquisition of business, net of cash acquired	(19,869)	0
Net cash used in investing activities	(24,277)	(7,656)
Financing activities
Repurchase of common stock	0	0
Proceeds from exercise of stock options	403	155
Excess tax benefits of stock options and awards	0	11
Net cash used in financing activities	403	166
Effect of exchange rate changes on cash activities	3,091	(3,003)
Increase (decrease) in cash and cash equivalents	(9,307)	42,030
Cash and cash equivalents at beginning of period	423,497	381,336
Cash and cash equivalents at end of period	$ 414,190	$ 423,366