CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net (loss) income	$ (73,725)	$ (70,513)	$ 34,944
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Gain on divestiture	0	(1,459)	0
Depreciation and amortization	54,987	49,000	33,162
Impairment of goodwill and long-lived assets	61,109	64,206	0
Deferred income taxes	(4,368)	(14,585)	636
Employee benefit plans settlement expenses	385	25,247	0
Stock-based compensation	3,456	2,829	2,081
Inventory step-up amortization	0	0	1,975
Loss (gain) on disposition of property, plant and equipment	237	(17)	230
Income from equity method investment	(37)	(148)	(132)
Changes in operating assets and liabilities:
Accounts receivable	(11,651)	37,470	(7,127)
Contract assets	(3,555)	(5,514)	(3,828)
Inventories	3,946	2,619	(6,001)
Income taxes receivable	(3,076)	(876)	3,151
Prepaid expenses and other assets	199	2,031	(542)
Accounts payable	26,161	(393)	(5,055)
Restructuring liabilities	9,323	(39)	(186)
Accrued payroll and other compensation	6,538	4,597	(2,352)
Deferred revenue	1,355	(4,267)	3,801
Accrued taxes payable	2,334	2,500	535
Benefit plan liabilities	(1,852)	(4,288)	(7,658)
Other, net	2,401	(1,538)	(2,895)
Net cash provided by operating activities	74,167	86,862	44,739
Cash flows from investing activities:
Capital expenditures	(33,449)	(35,850)	(31,291)
Proceeds from the sale of property, plant and equipment	46	298	298
Proceeds from divestitures	0	2,298	0
Collections of finance receivables	5,770	0	0
Business acquisitions, net of cash acquired	0	869	(269,972)
Net cash used for investing activities	(27,633)	(32,385)	(300,965)
Cash flows from financing activities:
Proceeds from borrowings	20,000	0	338,000
Debt repayments	(22,000)	(52,233)	(89,862)
Debt issuance costs	0	0	(538)
Common stock issued	2,174	448	850
Common stock repurchased	(269)	(142)	(974)
Net cash (used for) provided by financing activities	(95)	(51,927)	247,476
Effect of exchange rate changes on cash	4,406	(456)	(1,888)
Increase (decrease) in cash and cash equivalents	50,845	2,094	(10,638)
Cash and cash equivalents at beginning of period	51,331	49,237	59,875
Cash and cash equivalents at end of period	102,176	51,331	49,237
Cash paid during the year for:
Interest	14,890	14,064	5,960
Income taxes, net	$ 3,031	$ 5,863	$ 4,606