Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities:
Net income (loss)	$ (23,641)	$ 8,555
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation	9,541	9,320
Amortization	2,843	2,953
Deferred income taxes	39,000	74
Asset impairments	0	0
Gain on the sale of property, plant and equipment	(46)	(197)
Stock-based compensation expense	2,870	2,160
Excess tax benefit from stock-based compensation	0	0
Changes in operating assets and liabilities, net of effects from business acquisitions:
Accounts receivable	33,419	59,685
Contract assets	(1,127)	6,561
Inventories	(38,210)	(29,582)
Prepaid expenses and other assets	5,944	(3,292)
Accounts payable	2,337	16,225
Accrued liabilities	(9,116)	5,256
Income taxes	716	187
Net cash provided by operations	24,530	77,905
Cash flows from investing activities:
Proceeds from sales of investments at par	0	0
Additions to property, plant and equipment	(20,059)	(7,012)
Proceeds from the sale of property, plant and equipment	57	217
Additions to purchased software	(818)	(566)
Business acquisitions, net of cash acquired	0	0
Other	(179)	(108)
Net cash used in investing activities	(20,999)	(7,469)
Cash flows from financing activities:
Proceeds from stock options exercised	3,079	5,141
Excess tax benefits from stock-based compensation	0	0
Employee taxes paid for shares withheld	(763)	(358)
Borrowings under credit agreement	50,000	0
Principal payments on long-term debt and capital lease obligations	(54,551)	(3,082)
Share repurchases	(58,381)	(1,000)
Equity forward contract related to accelerated share repurchase	(10,000)	0
Debt issuance costs	0	(434)
Net provided by (used in) financing activities	(70,616)	267
Effect of exchange rate changes	866	341
Net increase (decrease) in cash and cash equivalents	(66,219)	71,044
Cash and cash equivalents at beginning of year	742,546	681,433
Cash and cash equivalents at end of period	$ 676,327	$ 752,477