CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 222,680	$ 195,540
Accounts receivable, net	211,081	218,271
Contract assets, net	84,578	79,070
Inventories	109,426	95,149
Income taxes prepaid and receivable	5,922	6,162
Prepaid expenses and other current assets	25,827	24,142
Total current assets	659,514	618,334
Property, plant and equipment, net	446,890	466,462
Intangibles, net	51,323	52,892
Goodwill	179,366	180,934
Deferred income taxes	48,260	51,621
Noncurrent receivables, net	38,929	41,234
Other assets	59,349	62,891
Total assets	1,483,631	1,474,368
Current liabilities:
Accounts payable	58,874	65,203
Accrued liabilities	110,071	125,885
Current maturities of long-term debt	20	20
Income taxes payable	6,656	11,611
Total current liabilities	175,621	202,719
Long-term debt	491,002	424,009
Other noncurrent liabilities	134,918	132,725
Deferred taxes and other liabilities	12,529	12,226
Total liabilities	814,070	771,679
SHAREHOLDERS' EQUITY
Preferred stock, par value $5.00 per share; authorized 2,000,000 shares; none issued
Additional paid in capital	431,836	432,518
Retained earnings	700,021	698,496
Accumulated items of other comprehensive income:
Translation adjustments	(148,599)	(122,852)
Pension and postretirement liability adjustments	(49,104)	(49,994)
Derivative valuation adjustment	(10,843)	(3,135)
Treasury stock (Class A), at cost; 8,408,770 shares in 2020 and 2019	(256,391)	(256,391)
Total Company shareholders' equity	666,961	698,683
Noncontrolling interest	2,600	4,006
Total equity	669,561	702,689
Total liabilities and shareholders' equity	1,483,631	1,474,368
Common Class A [Member]
SHAREHOLDERS' EQUITY
Common Stock	39	39
Accumulated items of other comprehensive income:
Total equity	39	39
Common Class B [Member]
SHAREHOLDERS' EQUITY
Common Stock	2	2
Accumulated items of other comprehensive income:
Total equity	$ 2	$ 2