Long-term and Short-term Debt (Details Textuals 2) $ in Millions	12 Months Ended
	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2013 USD ($)
Debt Disclosure [Abstract]
Interest payments	$ 60.8	$ 58.1	$ 59.7
Former Credit Facility [Member]
Line of Credit Facility [Line Items]
Borrowing capacity		$ 750.0
New Credit Facility [Member]
Line of Credit Facility [Line Items]
Borrowing capacity	$ 1,000.0
Expiration date	Mar. 24, 2020
Option to increase borrowing capacity of credit facility	$ 350.0
Non US Facilities [Member]
Line of Credit Facility [Line Items]
Borrowing capacity	$ 121.2
Maximum [Member] | New Credit Facility [Member]
Line of Credit Facility [Line Items]
Maximum debt to total capital ratio required by debt covenants	0.60