Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 183,284	$ 74,141
Trade receivables, less allowances of $1,061 and $341 at respective dates	75,144	110,622
Other receivables	20,891	6,748
Inventories, net	138,542	123,184
Prepaid expenses and other current assets	4,217	7,960
Total current assets	422,078	322,655
Property, plant and equipment, net	254,299	217,092
Goodwill	43,626	40,323
Intangible assets, net	13,868	14,800
Deferred income taxes	3,198	13,061
Other non-current assets	3,496	3,934
Total assets	740,565	611,865
Current liabilities:
Accounts payable	35,017	42,873
Deferred revenue and advance payments	4,707	7,506
Taxes payable	43	9,469
Accrued expenses and other current liabilities	42,774	35,614
Total current liabilities	82,541	95,462
Advance payments	39,000	39,000
Deferred income taxes	7,806	6,921
Accrued pension benefits	41,141	43,109
Other non-current liabilities	25,213	21,946
Total liabilities	195,701	206,438
Commitments and contingencies (see Notes 19 and 20)
Stockholders' equity:
Common Stock, $.10 par value; authorized 100,000,000 issued 34,270,975 and 33,927,595 shares at respective dates	3,427	3,393
Additional paid-in capital	165,979	153,681
Retained earnings	429,826	327,376
Treasury stock, at cost, 1,424,153 and 1,583,909 shares at respective dates	(12,140)	(13,503)
Accumulated other comprehensive loss	(42,228)	(65,520)
Total stockholders' equity	544,864	405,427
Total liabilities and stockholders' equity	$ 740,565	$ 611,865