CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities:
Net income (loss)	$ 2,729	$ (21,975)	$ 512,218
Adjustments to reconcile net income (loss) to net cash provided (used) by operating activities:
Depreciation	131,449	125,765	119,803
Amortization	35,224	33,937	18,592
Loss on early extinguishment of debt	2,668	0	5,314
Deferred income tax expense (benefit)	(16,930)	1,115	6,815
Equity (income) loss of unconsolidated entities, net	302	(186)	(273)
Dividends from unconsolidated entities	269	216	125
Gain on sale from discontinued businesses	0	(18,281)	(569,135)
Other, net	2,062	310	1,764
Changes in assets and liabilities:
Accounts receivable	(19,781)	34,221	(3,464)
Income tax refunds receivable from acquisition, reimbursable to seller	2,870	(11,032)	0
Insurance receivable	0	0	195,000
Inventories	(7,783)	(12,281)	(42,484)
Contract assets	(43,510)	(28,376)	(21,795)
Right-of-use-assets	28,300	25,400	15,164
Accounts payable	14,118	(14,452)	13,407
Accrued interest payable	(411)	(2,422)	14,723
Accrued compensation	6,469	2,921	(15,759)
Advances on contracts and other customer advances	(14,311)	10,492	(4,172)
Operating lease liabilities	(27,307)	(24,785)	(14,740)
Insurance liability	0	0	(195,000)
Income taxes payable - gain on sale of discontinued businesses	0	(12,373)	12,373
Retirement plan liabilities, net	(45,786)	(33,257)	(24,022)
Other assets and liabilities	21,556	(1,139)	(24,617)
Net cash provided (used) by operating activities	72,197	53,818	(163)
Cash flows from investing activities:
Purchases of property, plant and equipment	(158,326)	(120,224)	(184,973)
Proceeds from sale of businesses	0	37,219	658,414
Purchase of businesses, net of cash acquired*	0	(432,855)	(623,495)
Proceeds from sales of assets	16,724	6,204	17,022
Expenditures for intangible assets	(358)	(317)	(1,311)
Proceeds from notes receivable	6,400	0
Purchase of equity method investment	0	0	(2,364)
Payments for interest rate swap terminations	0	0	(2,758)
Net proceeds (payments) from settlement of foreign currency forward exchange contracts	10,940	(10,519)	7,273
Other investing activities, net	171	(152)	0
Net cash used by investing activities	(124,449)	(520,644)	(132,192)
Cash flows from financing activities:
Short-term borrowings, net	935	1,612	(5,398)
Current maturities and long-term debt:
Additions	540,663	638,717	848,314
Reductions	(464,848)	(139,887)	(661,620)
Dividends paid to noncontrolling interests	(3,103)	(2,978)	(4,712)
Noncontrolling Interest - purchase or sale	0	(561)	4,026
Stock-based compensation - Employee taxes paid	(3,392)	(4,303)	(11,234)
Common stock acquired for treasury	0	0	(31,838)
Payment of contingent consideration	(1,588)	(2,342)	0
Deferred financing costs	(7,828)	(1,928)	(11,272)
Other financing activities, net	(601)	(1,372)	(532)
Net cash provided by financing activities	60,238	486,958	125,734
Effect of exchange rate changes on cash, including restricted cash	(527)	(195)	(793)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect	7,459	19,937	(7,414)
Cash and cash equivalents, including restricted cash, at beginning of period	79,669	59,732	67,146
Cash and cash equivalents, including restricted cash, at end of period	87,128	79,669	59,732
Supplemental Cash Flow Information [Abstract]
Change in accrual for purchases of property, plant and equipment included in accounts payable	4,253	3,559	5,164
Purchase of businesses, net of cash acquired
Working capital	532	(33,387)	(26,663)
Property, plant and equipment	823	(102,258)	(77,295)
Goodwill	(1,232)	(153,562)	(330,230)
Long-term debt acquired	0	0	605
Other noncurrent assets and liabilities, net	(123)	(143,648)	(189,912)
Net cash used to acquire businesses	$ 0	$ (432,855)	$ (623,495)