Condensed Consolidated Statement of Stockholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Other Capital	Treasury Stock	Accumulated Deficit	Accumulated Other Comprehensive Loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of change in accounting guidance | ASU 2014-09	$ 37.6				$ 37.6
Beginning balance (in shares) at Dec. 31, 2017		73.6
Beginning balance at Dec. 31, 2017	102.4	$ 7.4	$ 503.1	$ (64.5)	(71.0)	$ (272.6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	14.0				14.0
Amortization of actuarial losses and prior service credits, net of income taxes	12.5					12.5
Repurchase of shares for withholding taxes and option costs under employee equity plans (in shares)		0.0
Repurchase of shares for withholding taxes and option costs under employee equity plans	(1.6)		(1.6)
Stock-based compensation and other, net (in shares)		0.2
Stock-based compensation and shares issued under equity plans	4.3	$ 0.0	4.3
Ending balance (in shares) at Mar. 31, 2018		73.8
Ending balance at Mar. 31, 2018	$ 169.2	$ 7.4	$ 505.8	$ (64.5)	$ (19.4)	$ (260.1)