CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Millions	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Common Stock in Treasury, at Cost
Balance at Sep. 30, 2017	$ 2,307.4	$ 0.9	$ 802.2	$ 2,399.8	$ (125.0)	$ (770.5)
Changes in Equity
Net income	56.4			56.4
Employee pension and postretirement benefits, net of tax	0.5				0.5
Currency translation adjustments	2.1				2.1
Cash dividends	(18.0)			(18.0)
Repurchases of Common Stock	(63.7)					(63.7)
Exercise of stock options	8.6		(1.8)			10.4
Stock-based compensation expense	7.5		7.5
Payment of stock-based restricted and performance shares	0.0		(8.6)			8.6
Shares tendered for taxes on stock-based compensation	(7.4)					(7.4)
Balance at Dec. 31, 2017	2,293.4	0.9	799.3	2,438.2	(122.4)	(822.6)
Balance at Sep. 30, 2018	2,513.5	0.7	814.8	2,007.9	(106.8)	(203.1)
Changes in Equity
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification | Accounting Standards Update 2014-09 [Member]	(60.4)			(60.4)
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification | Accounting Standards Update 2016-16 [Member]	44.5			44.5
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification | Accounting Standards Update 2018-02 [Member]	0.0			9.1	(9.1)
Balance at Oct. 01, 2018	2,497.6	0.7	814.8	2,001.1	(115.9)	(203.1)
Balance at Sep. 30, 2018	2,513.5	0.7	814.8	2,007.9	(106.8)	(203.1)
Changes in Equity
Net income	109.0			109.0
Net income | Accounting Standards Update 2014-09 [Member]	19.2
Employee pension and postretirement benefits, net of tax	0.0
Currency translation adjustments	(8.8)				(8.8)
Cash dividends	(19.3)			(19.3)
Repurchases of Common Stock	(170.0)					(170.0)
Exercise of stock options	1.7		(1.8)			3.5
Stock-based compensation expense	7.9		7.9
Payment of stock-based restricted and performance shares	0.0		(23.3)			23.3
Shares tendered for taxes on stock-based compensation	(6.9)					(6.9)
Balance at Dec. 31, 2018	$ 2,411.2	$ 0.7	$ 797.6	$ 2,090.8	$ (124.7)	$ (353.2)