Statement of Consolidated Stockholders' Equity (USD $) In Millions, except Share data, unless otherwise specified	Total	Common Stock	Additional Paid in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Loss
Beginning balance at Dec. 31, 2014	$ 1,015.9	$ 0.2	$ 1,028.5	$ 280.4	$ (197.1)	$ (96.1)
Beginning balance, shares at Dec. 31, 2014	17,607,251	17,607,251
Stockholders' Equity [Roll Forward]
Net income	(292.2)			(292.2)
Other comprehensive income, net of tax	66.9					66.9
Issuance of non-vested shares to employees, shares		51,510
Issuance of common shares to employees upon vesting of restricted stock units and performance shares, shares		50,809
Cancellation of employee non-vested shares		(540)
Cancellation of shares to cover employees’ tax withholdings upon vesting of non-vested shares, shares		(33,628)
Cancellation of shares to cover employees’ tax withholdings upon vesting of non-vested shares	(2.5)		(2.5)
Repurchase of common stock, shares	(405,259)	(405,259)
Repurchase of common stock	(30.0)				(30.0)
Cash dividends on common stock ($0.40 per share)	(7.1)			(7.1)
Excess tax benefit upon vesting of non-vested shares and dividend payment on unvested shares expected to vest	1.0		1.0
Amortization of unearned equity compensation	2.1		2.1
Restricted Stock Award, Forfeitures, Dividends	(0.2)			0.2
Ending balance at Mar. 31, 2015	$ 754.3	$ 0.2	$ 1,029.1	$ (18.7)	$ (227.1)	$ (29.2)
Ending balance, shares at Mar. 31, 2015	17,270,143	17,270,143