Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Cash flows from operating activities:
Net income (loss)	$ (12,698)	$ 26,629
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation	19,373	18,414
Amortization	5,710	5,903
Deferred income taxes	10,936	1,360
Asset impairments	96	0
Gain on the sale of property, plant and equipment	(116)	(167)
Stock-based compensation expense	5,405	4,505
Changes in operating assets and liabilities, net of effects from business acquisition:
Accounts receivable	(8,980)	49,394
Contract assets	(1,735)	3,466
Inventories	(52,063)	(39,478)
Prepaid expenses and other assets	1,966	(7,233)
Accounts payable	23,103	16,675
Accrued liabilities	(16,025)	13,388
Income taxes	8,846	(327)
Net cash provided by (used in) operations	(16,182)	92,529
Cash flows from investing activities:
Proceeds from sales of investments at par	522	250
Additions to property, plant and equipment	(36,708)	(24,039)
Proceeds from the sale of property, plant and equipment	137	235
Additions to purchased software	(1,655)	(2,340)
Business acquisition, net of cash acquired	(2,731)	0
Other	(129)	(105)
Net cash used in investing activities	(40,564)	(25,999)
Cash flows from financing activities:
Proceeds from stock options exercised	3,377	8,094
Employee taxes paid for shares withheld	(771)	(379)
Dividends paid	(7,136)	0
Borrowings under credit agreement	50,000	0
Principal payments on long-term debt and capital lease obligations	(59,121)	(6,185)
Share repurchases	(65,868)	(2,000)
Equity forward contract related to accelerated share repurchase	(10,000)	0
Debt issuance costs	0	(433)
Net used in financing activities	(89,519)	(903)
Effect of exchange rate changes	(642)	2,251
Net increase (decrease) in cash and cash equivalents	(146,907)	67,878
Cash and cash equivalents at beginning of year	742,546	681,433
Cash and cash equivalents at end of period	$ 595,639	$ 749,311