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	$ 1,565	$ 1,227
Adjustments to reconcile net income to net cash used by operating activities:
Depreciation	32,748	29,933
Amortization	8,967	6,557
Deferred income tax (benefit) expense	(3,421)	4,412
Equity (income) loss of unconsolidated entities, net	119	(96)
Gain on sale from discontinued business	0	(18,462)
Loss on early extinguishment of debt	2,668	0
Other, net	1,128	(2,007)
Changes in assets and liabilities, net of acquisitions and dispositions of businesses:
Accounts receivable	(16,446)	(22,050)
Inventories	407	(16,412)
Contract assets	(19,070)	(20,311)
Right-of-use assets	6,768	3,429
Accounts payable	(8,592)	12,308
Accrued interest payable	(7,320)	(9,891)
Accrued compensation	(1,541)	(2,752)
Advances on contracts	(9,698)	40,464
Operating lease liabilities	(6,750)	(3,358)
Retirement plan liabilities, net	(19,267)	(15,534)
Income taxes payable - Gain on sale of discontinued businesses	0	3,843
Other assets and liabilities	14,562	(2,836)
Net cash used by operating activities	(23,173)	(11,536)
Cash flows from investing activities:
Purchases of property, plant and equipment	(27,382)	(27,894)
Purchases of businesses, net of cash acquired	0	(4,157)
Proceeds from Divestiture of Businesses	0	37,219
Proceeds from sales of assets	3,862	2,185
Expenditures for intangible assets	(68)	(58)
Net proceeds (payments) from settlement of foreign currency forward exchange contracts	(1,427)	11,327
Other investing activities, net	46	0
Net cash provided (used) by investing activities	(24,969)	18,622
Cash flows from financing activities:
Short-term borrowings, net	575	3,697
Current maturities and long-term debt:
Additions	434,873	52,875
Reductions	(374,530)	(38,709)
Stock-based compensation - Employee taxes paid	(2,485)	(3,437)
Deferred financing costs	(6,525)	(1,632)
Other financing activities, net	(400)	0
Net cash provided by financing activities	51,508	12,794
Effect of exchange rate changes on cash and cash equivalents, including restricted cash	(710)	(10,824)
Net increase in cash and cash equivalents, including restricted cash	2,656	9,056
Cash and cash equivalents, including restricted cash, at beginning of period	79,669	59,732
Cash and cash equivalents, including restricted cash, at end of period	82,325	68,788
Supplemental Cash Flow Information [Abstract]
Change in accrual for purchases of property, plant and equipment included in accounts payable	$ 1,865	$ (281)