Condensed Consolidated Statements Of Cash Flows (unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities:
Net income	$ 445	$ 23,220
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	18,813	18,420
Amortization	5,718	5,705
Provision for doubtful accounts	2,107	(1,462)
Deferred income taxes	(330)	1,555
Gain on the sale of property, plant and equipment	(139)	(25)
Asset impairments	1,214	834
Stock-based compensation expense	6,044	5,720
Changes in operating assets and liabilities, net of effects from business acquisition:
Accounts receivable	20,356	106,749
Contract assets	7,420	(15,464)
Inventories	(48,668)	(6,327)
Prepaid expenses and other assets	(1,234)	1,559
Accounts payable	6,980	(49,428)
Accrued liabilities	3,091	(13,243)
Operating leases	236	574
Income taxes	(2,135)	(9,615)
Net cash provided by operations	19,918	68,772
Cash flows from investing activities:
Proceeds from sales of investments at par	0	50
Additions to property, plant and equipment	(21,402)	(14,163)
Proceeds from the sale of property, plant and equipment	307	28
Additions to purchased software	(1,888)	(1,332)
Cash received from business divestitures	2,214	0
Other	55	(29)
Net cash used in investing activities	(20,714)	(15,446)
Cash flows from financing activities:
Proceeds from stock options exercised	364	693
Employee taxes paid for shares withheld	(1,801)	(1,242)
Dividends paid	(11,365)	(12,079)
Borrowings under credit agreement	110,000	0
Principal payments on long-term debt	(84,392)	(2,441)
Share repurchases	(19,329)	(100,039)
Net cash used in financing activities	(6,523)	(115,108)
Effect of exchange rate changes	(218)	293
Net decrease in cash and cash equivalents and restricted cash	(7,537)	(61,489)
Cash and cash equivalents and restricted cash at beginning of period	363,956	458,102
Cash and cash equivalents and restricted cash at end of period	$ 356,419	$ 396,613