Condensed Consolidated Statements Of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities:
Net income	$ 6,360	$ 30,356
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	28,400	27,920
Amortization	8,539	8,469
Provision for doubtful accounts	2,160	(1,462)
Deferred income taxes	(4,079)	206
Gain on the sale of property, plant and equipment	(114)	(60)
Asset impairments	6,950	834
Stock-based compensation expense	9,464	8,461
Changes in operating assets and liabilities, net of effects from business acquisition:
Accounts receivable	16,410	121,171
Contract assets	(335)	(20,986)
Inventories	(37,131)	(6,557)
Prepaid expenses and other assets	1,675	2,944
Accounts payable	(18,260)	(122,156)
Customer deposits	21,074	8,546
Accrued liabilities	(13,498)	7,755
Operating leases	942	652
Income taxes	(2,942)	(8,779)
Net cash provided by operations	25,615	57,314
Cash flows from investing activities:
Proceeds from sales of investments at par	0	50
Additions to property, plant and equipment	(26,108)	(23,746)
Proceeds from the sale of property, plant and equipment	314	231
Additions to purchased software	(2,994)	(2,196)
Cash received from business divestitures	2,214	0
Other	58	(29)
Net cash used in investing activities	(26,516)	(25,690)
Cash flows from financing activities:
Proceeds from stock options exercised	371	1,350
Employee taxes paid for shares withheld	(1,913)	(1,318)
Dividends paid	(17,205)	(17,731)
Borrowings under credit agreement	110,000	0
Principal payments on long-term debt	(101,605)	(4,614)
Share repurchases	(19,329)	(118,350)
Net cash used in financing activities	(29,681)	(140,663)
Effect of exchange rate changes	1,436	(1,021)
Net decrease in cash and cash equivalents and restricted cash	(29,146)	(110,060)
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	$ 334,810	$ 348,042