Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities:
Net income	$ 23,351	$ 6,360
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation	26,335	28,400
Amortization	6,628	8,539
Provision for doubtful accounts	40	2,160
Deferred income taxes	(2,110)	(4,079)
Asset impairments	4,358	6,950
(Gain) loss on the sale of property, plant and equipment	164	(114)
Stock-based compensation expense	10,856	9,464
Changes in operating assets and liabilities
Accounts receivable	(2,342)	16,410
Contract assets	(17,415)	(335)
Inventories	(151,518)	(37,131)
Prepaid expenses and other assets	(9,470)	1,675
Accounts payable	114,477	(18,260)
Advance payments from customers	7,341	21,074
Accrued liabilities	(9,087)	(13,498)
Operating leases	(196)	942
Income taxes	(2,720)	(2,942)
Net cash provided by (used in) operations	(1,308)	25,615
Cash flows from investing activities:
Additions to property, plant and equipment	(29,497)	(26,108)
Proceeds from the sale of property, plant and equipment	222	314
Additions to purchased software	(2,940)	(2,994)
Cash received from business divestitures	0	2,214
Other	72	58
Net cash used in investing activities	(32,143)	(26,516)
Cash flows from financing activities:
Proceeds from stock options exercised	346	371
Employee taxes paid for with shares withheld	(3,152)	(1,913)
Dividends paid	(17,448)	(17,205)
Borrowings under credit agreement	30,000	110,000
Principal payments on credit agreement	(35,625)	(100,625)
Principal payments on finance leases	(833)	(980)
Share repurchases	(40,216)	(19,329)
Net cash provided by financing activities	(66,928)	(29,681)
Effect of exchange rate changes	(4,414)	1,436
Net decrease in cash and cash equivalents and restricted cash	(104,793)	(29,146)
Cash and cash equivalents and restricted cash at beginning of year	395,990	363,956
Cash and cash equivalents and restricted cash at end of period	$ 291,197	$ 334,810