Condensed Consolidated Statements of Stockholders' Equity Statement - USD ($) $ in Millions	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Common Stock in Treasury	Accumulated Other Comprehensive Loss, Net of Taxes
Balance at beginning of period at Dec. 31, 2016	$ 609.7	$ 22.8	$ 1,974.1	$ 1,040.0	$ (1,478.1)	$ (949.1)
Effect of contingent stock transactions	(12.6)	0.2	8.9		(21.7)
Stock issued for share-based incentive compensation	22.2		0.5		21.7
Recognition of pension items, net of taxes	4.5					4.5
Foreign currency translation adjustments	55.2					55.2
Unrealized loss on derivative instruments, net of taxes	(9.6)					(9.6)
Net loss	(43.2)			(43.2)
Dividends on common stock ($0.16 per share)	(31.4)			(31.4)
Balance at end of period at Mar. 31, 2017	594.8	23.0	1,983.5	965.4	(1,478.1)	(899.0)
Balance at beginning of period at Dec. 31, 2017	152.3	23.0	1,939.6	1,735.2	(2,700.6)	(844.9)
Effect of contingent stock transactions	0.1	0.2	6.2		(6.3)
Stock issued for share-based incentive compensation	20.7				20.7
Repurchases of common stock	(324.7)		80.0		(404.7)
Recognition of pension items, net of taxes	0.6					0.6
Foreign currency translation adjustments	28.4					28.4
Unrealized loss on derivative instruments, net of taxes	(9.9)					(9.9)
Net loss	(200.6)			(200.6)
Dividends on common stock ($0.16 per share)	(26.6)			(26.6)
Balance at end of period at Mar. 31, 2018	$ (364.8)	$ 23.2	$ 2,025.8	$ 1,502.9	$ (3,090.9)	$ (825.8)