Statement of Consolidated Cash Flows (Unaudited) - USD ($) $ in Millions		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016
Cash flows from operating activities:
Net income		$ 60.6	$ 67.2
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation of property, plant and equipment		28.3	25.5
Amortization of definite-lived intangible assets		1.0	1.2
Amortization of debt discount and debt issuance costs		0.9	0.8
Deferred income taxes		38.6	40.7
Non-cash equity compensation		10.1	8.8
Lower of cost or market inventory write-down		0.0	4.9
Gain on sale of available for sale securities		(1.8)	0.0
Non-cash unrealized gain on derivative instruments		(14.0)	(16.9)
Loss on extinguishment of debt		0.0	11.1
Non-cash intangible asset impairment charge		18.4	2.6
(Gain) loss on disposition of property, plant and equipment		(0.4)	0.2
Non-cash net periodic postretirement benefit cost relating to Salaried VEBA		3.4	2.5
Other non-cash changes in assets and liabilities		(0.8)	1.1
Changes in operating assets and liabilities:
Trade and other receivables		(4.0)	(26.7)
Inventories, excluding lower of cost or market write-down		(10.6)	(8.9)
Prepaid expenses and other current assets		(1.8)	(0.9)
Accounts payable		21.6	0.8
Accrued liabilities		0.9	27.9
Annual variable cash contributions to VEBAs		(20.0)	(19.5)
Long-term assets and liabilities, net		1.1	(15.0)
Net cash provided by operating activities		131.5	107.4
Cash flows from investing activities
Capital expenditures		(56.1)	(57.4)
Purchase of available for sale securities		(196.0)	(201.1)
Proceeds from disposal of property, plant and equipment		237.2	30.0
Proceeds from disposal of property, plant and equipment		0.6	0.0
Net cash used in investing activities	[1]	(14.3)	(228.5)
Cash flows from financing activities
Repayment of principal and redemption premium of 8.25% Senior Notes		0.0	(206.0)
Issuance of 5.875% Senior Notes		0.0	375.0
Cash paid for debt issuance costs		0.0	(6.8)
Proceeds from stock option exercises		0.0	1.0
Repayment of capital lease		(0.2)	(0.1)
Cancellation of shares to cover employees' tax withholdings upon vesting of non-vested shares		(4.5)	(2.8)
Repurchase of common stock		(66.7)	(13.6)
Cash dividends and dividend equivalents paid		(26.4)	(24.4)
Net cash (used in) provided by financing activities	[1]	(97.8)	122.3
Net increase in cash, cash equivalents and restricted cash during the period		19.4	1.2
Cash, cash equivalents and restricted cash at beginning of period		67.7	83.7
Cash, cash equivalents and restricted cash at end of period		$ 87.1	$ 84.9

[1] See Note 12 for the supplemental disclosure on non-cash transactions.