CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities:
Net income (loss)	$ (38,680)	$ 1,565
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation	33,604	32,748
Amortization	8,586	8,967
Deferred income tax (benefit) expense	(4,275)	(3,421)
Equity (income) loss of unconsolidated entities, net	131	119
Dividends from unconsolidated entities	178	0
Loss on early extinguishment of debt	0	2,668
Other, net	259	1,128
Changes in assets and liabilities, net of acquisitions and dispositions of businesses:
Accounts receivable	(15,364)	(16,446)
Increase (Decrease) in Income Taxes Receivable	7,687	0
Inventories	(4,610)	407
Contract assets	4,843	(19,070)
Right-of-use assets	7,076	6,768
Accounts payable	1,655	(8,592)
Accrued interest payable	(7,393)	(7,320)
Accrued compensation	(5,692)	(1,541)
Advances on contracts	(7,808)	(9,698)
Operating lease liabilities	(7,063)	(6,750)
Retirement plan liabilities, net	(14,519)	(19,267)
Other assets and liabilities	7,070	14,562
Net cash used by operating activities	(34,315)	(23,173)
Cash flows from investing activities:
Purchases of property, plant and equipment	(32,958)	(27,382)
Proceeds from sales of assets	5,976	3,862
Expenditures for intangible assets	(54)	(68)
Net proceeds (payments) from settlement of foreign currency forward exchange contracts	1,061	(1,427)
Payments for settlements of interest rate swaps	1,062	0
Other investing activities, net	124	46
Net cash used by investing activities	(26,913)	(24,969)
Cash flows from financing activities:
Short-term borrowings, net	2,051	575
Current maturities and long-term debt:
Additions	72,005	434,873
Reductions	(2,566)	(374,530)
Stock-based compensation - Employee taxes paid	(1,377)	(2,485)
Payment of contingent consideration	(6,915)	0
Deferred financing costs	0	(6,525)
Other financing activities, net	0	(400)
Net cash provided by financing activities	63,198	51,508
Effect of exchange rate changes on cash and cash equivalents, including restricted cash	455	(710)
Net increase in cash and cash equivalents, including restricted cash	2,425	2,656
Cash and cash equivalents, including restricted cash, at beginning of period	87,128	79,669
Cash and cash equivalents, including restricted cash, at end of period	89,553	82,325
Supplemental Cash Flow Information [Abstract]
Change in accrual for purchases of property, plant and equipment included in accounts payable	$ (745)	$ 1,865