Condensed Consolidated Statements of Shareholders' Equity (unaudited) Statement - USD ($) $ in Millions	Total	Noncontrolling Interest [Member]	Treasury Stock [Member]	Common Stock [Member]	Parent [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Additional Paid-in Capital [Member]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 1,365.6	$ 7.4	$ (796.8)	$ 4.4	$ 1,358.2	$ 1,676.2	$ (110.0)	$ 584.4
Common Stock, Shares, Outstanding			22,643,840	65,813,794
Other Comprehensive Income (Loss), Net of Tax							25.2
Other Comprehensive Income (Loss), Net of Tax	35.5						35.5
Net Income	116.8				116.8
Net Income (Loss) Attributable to Parent	116.8
Stock Issued During Period, Value, Employee Stock Purchase Plan	3.4		$ 1.4		3.4			2.0
Stock Issued During Period, Shares, Employee Stock Purchase Plans			(38,772)	(38,772)
Adjustments to Additional Paid in Capital, Share-based Compensation, Restricted Stock Unit or Restricted Stock Award, Requisite Service Period Recognition								(4.9)
Stock Issued During Period, Value, Restricted Stock Award, Gross			$ 4.9
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period			(138,546)	138,546
Stock Issued During Period, Value, Stock Options Exercised	(10.5)		$ (11.1)		(10.5)			(0.6)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period			(314,762)	(314,762)
Share-based Compensation on Equity-Classified Awards	15.5				15.5			15.5
Dividends	(25.1)				(25.1)	(25.4)		(0.3)
Shares Paid for Tax Withholding for Share Based Compensation			53,811	(53,811)
Payments Related to Tax Withholding for Share-based Compensation	$ (4.4)				4.4
Other Comprehensive Income (Loss), Tax							3.7
Common Stock, Dividends, Per Share, Cash Paid	$ 0.38
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest | VIE Activity [Member]	$ (7.4)	(7.4)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	1,464.1	7.0	$ (787.3)	$ 4.4	1,457.1	1,752.5	(99.7)	587.2
Common Stock, Shares, Outstanding			22,317,811	66,139,823
Other Comprehensive Income (Loss), Net of Tax	25.2						25.2
Net Income	28.5				28.5
Net Income (Loss) Attributable to Parent	28.5
Stock Issued During Period, Value, Employee Stock Purchase Plan	1.9		$ 0.8		1.9			1.1
Stock Issued During Period, Shares, Employee Stock Purchase Plans			(21,092)	(21,092)
Adjustments to Additional Paid in Capital, Share-based Compensation, Restricted Stock Unit or Restricted Stock Award, Requisite Service Period Recognition								(1.0)
Stock Issued During Period, Value, Restricted Stock Award, Gross			$ 1.0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period			(27,679)	27,679
Stock Issued During Period, Value, Stock Options Exercised	(2.4)		$ (2.6)		(2.4)			(0.2)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period			(73,906)	(73,906)
Share-based Compensation on Equity-Classified Awards	9.4				9.4			9.4
Dividends	(13.2)				(13.2)	(13.4)		(0.2)
Shares Paid for Tax Withholding for Share Based Compensation			10,437	(10,437)
Payments Related to Tax Withholding for Share-based Compensation	$ (0.9)				0.9
Other Comprehensive Income (Loss), Tax							1.4
Common Stock, Dividends, Per Share, Cash Paid	$ 0.20
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest | VIE Activity [Member]	$ (7.0)	(7.0)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	1,510.4	$ 0.0	$ (783.8)	$ 4.4	1,510.4	1,767.6	(74.5)	596.7
Common Stock, Shares, Outstanding			22,205,571	66,252,063
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 1,616.2		$ (754.3)	$ 4.4		1,876.2	(113.0)	602.9
Common Stock, Shares, Outstanding	67,256,112		21,201,522	67,256,112
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ (5.4)
Cumulative Effect on Retained Earnings, Tax | Accounting Standards Update 2014-09 [Member]	4.8
Cumulative Effect on Retained Earnings, Tax | Accounting Standards Update 2016-16 [Member]	0.2
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification						5.4	(5.4)
Cumulative Effect on Retained Earnings, Net of Tax | Accounting Standards Update 2014-09 [Member]	(4.9)					(4.9)
Cumulative Effect on Retained Earnings, Net of Tax | Accounting Standards Update 2016-16 [Member]	(5.6)
Other Comprehensive Income (Loss), Net of Tax	(21.9)						(21.9)
Net Income	91.7
Net Income (Loss) Attributable to Parent	91.7
Stock Issued During Period, Value, Employee Stock Purchase Plan	4.2		$ 1.6					2.6
Stock Issued During Period, Shares, Employee Stock Purchase Plans			(42,244)	(42,244)
Adjustments to Additional Paid in Capital, Share-based Compensation, Restricted Stock Unit or Restricted Stock Award, Requisite Service Period Recognition								(4.7)
Stock Issued During Period, Value, Restricted Stock Award, Gross			$ 4.7
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period			(130,567)	130,567
Stock Issued During Period, Value, Stock Options Exercised	(8.6)		$ (6.6)					(2.0)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period			(178,203)	(178,203)
Share-based Compensation on Equity-Classified Awards	16.9							16.9
Dividends	(27.4)					(27.6)		(0.2)
Shares Paid for Tax Withholding for Share Based Compensation			43,135	(43,135)
Payments Related to Tax Withholding for Share-based Compensation	(4.0)
Treasury Stock, Shares, Acquired			(792,264)	(792,264)
Payments for Repurchase of Common Stock	$ 75.0				$ (75.0)
Other Comprehensive Income (Loss), Tax							(1.5)
Common Stock, Dividends, Per Share, Cash Paid	$ 0.41
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest						1,871.3
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 1,551.5		$ (824.4)	$ 4.4		1,899.9	(135.3)	606.9
Common Stock, Shares, Outstanding			21,799,747	66,657,887
Cumulative Effect on Retained Earnings, Net of Tax | Accounting Standards Update 2014-09 [Member]	49.5
Other Comprehensive Income (Loss), Net of Tax	(5.0)						(5.0)
Net Income	49.5
Net Income (Loss) Attributable to Parent	49.5
Stock Issued During Period, Value, Employee Stock Purchase Plan	2.3		$ 0.8					1.5
Stock Issued During Period, Shares, Employee Stock Purchase Plans			(20,799)	(20,799)
Adjustments to Additional Paid in Capital, Share-based Compensation, Restricted Stock Unit or Restricted Stock Award, Requisite Service Period Recognition								(0.7)
Stock Issued During Period, Value, Restricted Stock Award, Gross			$ 0.7
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period			(18,103)	18,103
Stock Issued During Period, Value, Stock Options Exercised	(4.0)		$ (3.0)					(1.0)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period			(80,628)	(80,628)
Share-based Compensation on Equity-Classified Awards	11.1							11.1
Dividends	(14.1)					(14.2)		(0.1)
Shares Paid for Tax Withholding for Share Based Compensation			5,690	(5,690)
Payments Related to Tax Withholding for Share-based Compensation	$ (0.5)
Other Comprehensive Income (Loss), Tax							(1.4)
Common Stock, Dividends, Per Share, Cash Paid	$ 0.21
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 1,598.8		$ (820.4)	$ 4.4		$ 1,935.2	$ (140.3)	$ 619.9
Common Stock, Shares, Outstanding			21,685,907	66,771,727