CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities:
Net income (loss)	$ (176,431)	$ 2,729	$ (21,975)
Adjustments to reconcile net income (loss) to net cash provided (used) by operating activities:
Depreciation	129,712	131,449	125,765
Amortization	34,137	35,224	33,937
(Gain) loss on early extinguishment of debt	(2,254)	2,668	0
Deferred income tax expense (benefit)	(12,029)	(16,930)	1,115
Equity (income) loss of unconsolidated entities, net	178	302	(186)
Dividends from unconsolidated entities	526	269	216
Gain on sale from discontinued businesses	0	0	(18,281)
Goodwill and other intangible asset impairment charges	119,580	0	0
Other, net	(427)	2,062	310
Changes in assets and liabilities:
Accounts receivable	94,317	(19,781)	34,221
Income tax refunds receivable from acquisition, reimbursable to seller	7,687	2,870	(11,032)
Inventories	(16,798)	(7,783)	(12,281)
Contract assets	11,543	(43,510)	(28,376)
Right-of-use-assets	29,171	28,300	25,400
Accounts payable	19,264	14,118	(14,452)
Accrued interest payable	(643)	(411)	(2,422)
Accrued compensation	(3,945)	6,469	2,921
Advances on contracts and other customer advances	(11,347)	(14,311)	10,492
Operating lease liabilities	(28,374)	(27,307)	(24,785)
Income taxes payable - gain on sale of discontinued businesses	0	0	(12,373)
Retirement plan liabilities, net	(34,136)	(45,786)	(33,257)
Other assets and liabilities	(9,204)	21,556	(1,139)
Net cash provided (used) by operating activities	150,527	72,197	53,818
Cash flows from investing activities:
Purchases of property, plant and equipment	(137,160)	(158,326)	(120,224)
Proceeds from sale of businesses	0	0	37,219
Purchase of businesses, net of cash acquired*	0	0	(432,855)
Proceeds from sales of assets	10,759	16,724	6,204
Expenditures for intangible assets	(184)	(358)	(317)
Proceeds from notes receivable	8,605	6,400	0
Payments for settlement of interest rate swaps	(2,304)	0	0
Net proceeds (payments) from settlement of foreign currency forward exchange contracts	20,950	10,940	(10,519)
Other investing activities, net	273	171	(152)
Net cash used by investing activities	(99,061)	(124,449)	(520,644)
Cash flows from financing activities:
Short-term borrowings, net	884	935	1,612
Current maturities and long-term debt:
Additions	224,445	540,663	638,717
Reductions	(256,310)	(464,848)	(139,887)
Dividends paid to noncontrolling interests	(4,841)	(3,103)	(2,978)
Noncontrolling Interest - purchase or sale	1,901	0	(561)
Stock-based compensation - Employee taxes paid	(1,949)	(3,392)	(4,303)
Payment of contingent consideration	(6,915)	(1,588)	(2,342)
Deferred financing costs	0	(7,828)	(1,928)
Other financing activities, net	0	(601)	(1,372)
Net cash (used) provided by financing activities	(42,785)	60,238	486,958
Effect of exchange rate changes on cash, including restricted cash	(10,715)	(527)	(195)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect	(2,034)	7,459	19,937
Cash and cash equivalents, including restricted cash, at beginning of period	87,128	79,669	59,732
Cash and cash equivalents, including restricted cash, at end of period	85,094	87,128	79,669
Supplemental Cash Flow Information [Abstract]
Change in accrual for purchases of property, plant and equipment included in accounts payable	10,845	4,253	3,559
Purchase of businesses, net of cash acquired
Working capital	0	532	(33,387)
Property, plant and equipment	0	823	(102,258)
Goodwill	0	(1,232)	(153,562)
Other noncurrent assets and liabilities, net	0	(123)	(143,648)
Net cash used to acquire businesses	$ 0	$ 0	$ (432,855)