Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cash flows from operating activities:
Net income	$ 7,917	$ 3,852
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	8,973	9,301
Amortization	2,082	2,891
Deferred income taxes	(161)	(885)
Asset impairments		1,007
Gain on the sale of property, plant and equipment	(8)	(31)
Stock-based compensation expense	2,850	2,739
Changes in operating assets and liabilities, net of effects from business acquisitions:
Accounts receivable	32,561	6,414
Contract assets	(5,426)	1,099
Inventories	(28,700)	(23,769)
Prepaid expenses and other assets	(6,675)	(3,110)
Accounts payable	42,439	14,882
Advance payments from customers	(7,289)	1,785
Accrued liabilities	(11,990)	(18,951)
Operating leases	(608)	(83)
Income taxes	648	(250)
Net cash provided by (used in) operations	36,613	(3,109)
Cash flows from investing activities:
Additions to property, plant and equipment	(5,770)	(11,856)
Proceeds from the sale of property, plant and equipment	13	7
Additions to purchased software	(652)	(1,040)
Cash received from business divestitures		1,341
Other		57
Net cash used in investing activities	(6,409)	(11,491)
Cash flows from financing activities:
Proceeds from stock options exercised	276	359
Employee taxes paid for shares withheld	(2,924)	(1,767)
Dividends paid	(5,805)	(5,538)
Borrowings under credit agreement		110,000
Principal payments on credit agreement	(1,875)	(16,875)
Principal payments on finance leases	(380)	(312)
Share repurchases	(13,052)	(19,329)
Net cash provided by (used in) financing activities	(23,760)	66,538
Effect of exchange rate changes	(2,006)	(4,108)
Net increase in cash and cash equivalents and restricted cash	4,438	47,830
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	$ 400,428	$ 411,786