Income Taxes - Schedule of Components of Income Tax Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Components Of Deferred Income Tax Assets And Liabilities [Line Items]
Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount	$ (4.6)	$ (6.4)	$ 4.9
Income (loss) from continuing operations before income taxes	151.2	175.8	(180.1)
Deferred income taxes	(6.8)	(32.5)	(7.0)
Reported income tax expense	48.3	31.6	39.6
H G I [Member]
Components Of Deferred Income Tax Assets And Liabilities [Line Items]
Current Federal Tax Expense (Benefit)	6.9	(0.4)	1.7
Deferred income taxes	(6.8)	(32.5)	(7.0)
Reported income tax expense	48.3	31.6	39.6
Current Foreign Tax Expense (Benefit)	47.4	60.2	40.4
Current State and Local Tax Expense (Benefit)	0.8	4.3	4.5
Current Income Tax Expense (Benefit)	55.1	64.1	46.6
Deferred Federal Income Tax Expense (Benefit)	8.8	(34.2)	(14.8)
Deferred Foreign Income Tax Expense (Benefit)	(5.9)	(1.1)	11.2
Deferred State and Local Income Tax Expense (Benefit)	(9.7)	2.8	(3.4)
Outside of the United States [Member]
Components Of Deferred Income Tax Assets And Liabilities [Line Items]
Income (loss) from continuing operations before income taxes	213.5	200.2	190.0
UNITED STATES
Components Of Deferred Income Tax Assets And Liabilities [Line Items]
Income (loss) from continuing operations before income taxes	$ (62.3)	$ (24.4)	$ (370.1)