Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 47.2	$ 60.1
Accounts receivable, net	270.3	248.7
Inventories, net	308.7	314.0
Contract assets	43.7
Prepaid expenses and other current assets	29.1	33.9
Total current assets	699.0	656.7
Property, plant and equipment	2,839.8	2,743.9
Less accumulated depreciation	(945.6)	(877.6)
Net property, plant and equipment	1,894.2	1,866.3
Goodwill and other intangible assets	144.6	148.7
Investments in affiliated companies	45.9	47.7
Other assets	62.8	61.5
Total assets	2,846.5	2,780.9
Current liabilities:
Current portion of debt	9.3	4.3
Accounts payable	143.1	144.1
Accrued compensation and benefits	68.1	73.0
Accrued liabilities	50.4	40.7
Total current liabilities	270.9	262.1
Commitments and contingencies (see Note 13)
Long-term debt	980.7	805.6
Retirement obligations	42.7	45.4
Other non-current liabilities	184.9	172.7
Total liabilities	1,479.2	1,285.8
Stockholders' equity:
Common stock, $0.01 par value, 200.0 shares authorized, 108.5 shares and 107.8 shares issued at September 30, 2018 and December 31, 2017, respectively	1.1	1.1
Additional paid-in capital	795.2	774.3
Retained earnings	1,673.3	1,496.1
Accumulated other comprehensive loss	(81.6)	(45.0)
Total stockholders' equity including treasury stock value	2,388.0	2,226.5
Less – Treasury stock, at cost, 22.4 shares at September 30, 2018, and 18.2 shares at December 31, 2017, respectively.	(1,020.7)	(731.4)
Total stockholders' equity	1,367.3	1,495.1
Total liabilities and stockholders' equity	$ 2,846.5	$ 2,780.9