Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 171,348	$ 183,284
Trade receivables, net	100,224	75,144
Contract assets	107,083
Other receivables	15,417	20,891
Inventories, net	99,562	138,542
Prepaid expenses and other current assets	10,589	4,217
Total current assets	504,223	422,078
Property, plant and equipment, net	266,075	254,299
Goodwill	42,864	43,626
Intangible assets, net	12,753	13,868
Deferred income taxes	1,448	3,198
Other non-current assets	3,532	3,496
Total assets	830,895	740,565
Current liabilities:
Accounts payable	51,596	35,017
Contract liabilities, current	8,153	4,707
Taxes payable	3,388	43
Accrued expenses and other current liabilities	33,304	42,774
Total current liabilities	96,441	82,541
Contract liabilities, non-current	39,000	39,000
Deferred income taxes	9,377	7,806
Accrued pension benefits	38,444	41,141
Other non-current liabilities	24,306	25,213
Total liabilities	207,568	195,701
Stockholders' equity:
Common stock, $.10 par value; authorized 100,000,000, issued 34,477,144 and 34,270,975 shares at respective dates	3,448	3,427
Additional paid-in capital	172,480	165,979
Retained earnings	510,522	429,826
Treasury stock, at cost, 1,273,888 and 1,424,153 shares at respective dates	(10,860)	(12,140)
Accumulated other comprehensive loss	(52,263)	(42,228)
Total stockholders' equity	623,327	544,864
Total liabilities and stockholders' equity	$ 830,895	$ 740,565