CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Assets
Cash and cash equivalents	$ 187,385	$ 197,755	$ 151,426	$ 183,727
Accounts receivable, net	234,127	223,176
Contract assets	57,869	57,447
Inventories	102,379	85,904
Income taxes prepaid and receivable	6,818	7,473
Prepaid expenses and other current assets	23,696	21,294
Total current assets	612,274	593,049
Property, plant and equipment, net	460,520	462,055
Intangibles, net	47,646	49,206
Goodwill	163,438	164,382
Deferred income taxes	63,736	62,622
Noncurrent receivables	45,354	45,061
Other assets	50,313	41,617
Total assets	1,443,281	1,417,992
LIABILITIES AND SHAREHOLDERS' EQUITY
Accounts payable	74,050	52,246
Accrued liabilities	122,342	129,030
Current maturities of long-term debt	19	1,224
Income taxes payable	8,387	6,806
Total current liabilities	204,798	189,306
Long-term debt	491,022	523,707
Other noncurrent liabilities	112,726	88,277
Deferred taxes and other liabilities	8,328	8,422
Total liabilities	816,874	809,712
SHAREHOLDERS' EQUITY
Preferred stock, par value $5.00 per share; authorized 2,000,000 shares; none issued
Additional paid in capital	430,052	430,555
Retained earnings	613,057	589,645
Accumulated items of other comprehensive income:
Translation adjustments	(116,630)	(115,976)
Pension and postretirement liability adjustments	(48,596)	(47,109)
Derivative valuation adjustment	1,846	4,697
Treasury stock (Class A), at cost; 8,418,620 shares in 2019 and in 2018	(256,603)	(256,603)
Total Company shareholders' equity	623,166	605,249
Noncontrolling interest	3,241	3,031
Total equity	626,407	608,280	$ 592,578	$ 57,301
Total liabilities and shareholders' equity	1,443,281	1,417,992
Common Class A [Member]
SHAREHOLDERS' EQUITY
Common Stock	37	37
Common Class B [Member]
SHAREHOLDERS' EQUITY
Common Stock	$ 3	$ 3