Statement of Consolidated Cash Flows - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash flows from operating activities:
Net (loss) income		$ (236.6)	$ 71.8	$ 104.8
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Depreciation of property, plant and equipment		30.8	29.5	26.4
Amortization of definite-lived intangible assets		1.6	1.6	1.7
Amortization of debt discount and debt issuance costs		4.3	11.8	11.0
Deferred income taxes – Note 5		(131.7)	34.3	55.4
Excess tax benefit upon vesting of non-vested shares and dividend payment on unvested shares expected to vest		1.3	0.8	1.1
Non-cash equity compensation		9.5	7.0	6.8
Lower of cost or market inventory write-down		2.6	0.0	0.0
Non-cash unrealized loss (gain) on derivative instruments		3.4	6.8	(3.9)
Amortization of option premiums (received) paid, net		0.0	0.0	(0.1)
Non-cash impairment charges		0.1	1.5	0.0
Loss on repurchase of Senior Notes	[1]	2.5	0.0	0.0
Loss on disposition of property, plant and equipment		(0.3)	(0.2)	(0.1)
Loss (gain) on disposition of available for sale securities		0.0	(0.1)	0.4
Non-cash defined benefit net periodic benefit cost (income)	[2]	2.8	(23.5)	(22.0)
Non-cash loss on removal of Union VEBA, net	[2]	446.7	0.0	0.0
Other non-cash changes in assets and liabilities		(0.6)	(0.6)	9.3
Changes in operating assets and liabilities:
Trade and other receivables		(17.4)	7.0	3.3
Inventories, excluding lower of cost or market write-down		7.5	0.3	28.4
Prepaid expenses and other current assets	[3]	(0.5)	0.6	(1.1)
Accounts payable		(13.6)	20.3	(1.6)
Accrued liabilities	[2],[3]	12.8	(6.0)	1.8
Annual variable cash contributions to VEBAs		13.7	16.0	20.0
Payable to affiliate		0.0	0.0	(7.9)
Long-term assets and liabilities, net	[2],[3]	(27.3)	7.2	(0.6)
Net cash provided by operating activities		158.8	124.1	111.7
Cash flows from investing activities:
Capital expenditures		(63.1)	(59.4)	(70.4)
Purchase of available for sale securities		(0.5)	(93.5)	(227.8)
Proceeds from disposition of available for sale securities		84.0	108.2	183.1
Change in restricted cash		0.0	0.0	1.7
Net cash provided by (used in) investing activities	[4]	20.4	(44.7)	(113.4)
Cash flows from financing activities:
Repurchase of Senior Notes	[1]	(30.0)	0.0	0.0
Settlement of Convertible Notes	[1]	(175.0)	0.0	0.0
Proceeds from cash-settled call options related to settlement of Convertible Notes	[1]	94.9	0.0	0.0
Payment for conversion premium related to settlement of Convertible Notes	[1]	(94.9)	0.0	0.0
Cash paid for financing costs		0.6	0.0	0.0
Payment of capital lease liability		0.0	(0.1)	(0.1)
Excess tax benefit upon vesting of non-vested shares and dividend payment on unvested shares expected to vest		1.3	0.8	1.1
Cancellation of shares to cover employees' tax withholdings upon vesting of non-vested shares		(2.8)	(2.4)	(2.5)
Repurchase of common stock		(49.2)	(44.1)	(78.3)
Cash dividends paid to stockholders		(28.1)	(25.4)	(23.0)
Cash dividend returned to the Company		0.0	0.0	0.6
Net cash used in financing activities	[4]	(284.4)	(71.2)	(102.2)
Net (decrease) increase in cash and cash equivalents during the period		(105.2)	8.2	(103.9)
Cash and cash equivalents at beginning of period		177.7	169.5	273.4
Cash and cash equivalents at end of period		$ 72.5	$ 177.7	$ 169.5

[1] See Note 3 for more information relating to the Senior Notes (defined in Note 3) and the Convertible Notes.

[2] See Note 6 for the impact of removing the Union VEBA (defined in Note 6) net assets.

[3] Excludes the reclassification of derivatives relating to the Convertible Notes (defined in Note 3) from long-term to current at December 31, 2014 as the amounts had no impact on cash flow - see Note 3 and Note 11.

[4] See Note 14 for the supplemental disclosure on non-cash transactions.