Consolidated Balance Sheets (Unaudited) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 164.0	$ 51.1
Short-term investments	71.9	183.7
Receivables:
Trade receivables, net	191.2	165.0
Other	18.9	15.5
Contract assets	52.6	0.0
Inventories	177.2	207.9
Prepaid expenses and other current assets	29.0	33.4
Total current assets	704.8	656.6
Property, plant and equipment, net	584.2	571.4
Deferred tax assets, net	51.5	72.0
Intangible assets, net	24.3	25.0
Goodwill	18.8	18.8
Other assets	40.2	41.4
Total	1,423.8	1,385.2
Current liabilities:
Accounts payable	132.0	90.0
Accrued salaries, wages and related expenses	32.2	42.6
Other accrued liabilities	29.9	40.5
Total current liabilities	194.1	173.1
Net liabilities of Salaried VEBA	31.8	31.9
Deferred tax liabilities	4.3	4.3
Long-term liabilities	62.6	60.0
Long-term debt	370.0	369.6
Total liabilities	662.8	638.9
Commitments and contingencies
Stockholders' equity:
Preferred stock, 5,000,000 shares authorized at both June 30, 2018 and December 31, 2017; no shares were issued and outstanding at June 30, 2018 and December 31, 2017	0.0	0.0
Common stock, par value $0.01, 90,000,000 shares authorized at both June 30, 2018 and at December 31, 2017; 22,471,592 shares issued and 16,665,941 shares outstanding at June 30, 2018; 22,393,537 shares issued and 16,773,586 shares outstanding at December 31, 2017	0.2	0.2
Additional paid in capital	1,054.7	1,055.9
Retained earnings	123.1	85.5
Treasury stock, at cost, 5,805,651 shares at June 30, 2018 and 5,619,951 shares at December 31, 2017, respectively	(378.0)	(358.6)
Accumulated other comprehensive loss	(39.0)	(36.7)
Total stockholders' equity	761.0	746.3
Total	$ 1,423.8	$ 1,385.2