Consolidated Statements of Comprehensive Income Statement (USD $) In Millions, unless otherwise specified	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Statement of Comprehensive Income [Abstract]
Net income	$ 19.3	$ 19.3	$ 12.7
Other comprehensive income (loss), net of tax [Abstract]
Foreign currency translation adjustment	(4.6)	(1.8)	(1.1)
Pension liabilities adjustment	(0.8)	2.9	(1.8)
Net unrealized gain or loss on available-for-sale securities	0.2	0.6	6.5
Reclassification of adjustment for gains included in net income:
Foreign currency translation adjustment (included in other income)	0	(0.1)	0
Periodic pension costs (included in compensation and benefits)	0.2	0.8	0.4
Realized gain on available-for-sale securities (included in trading gains, net)	(0.1)	(8.3)	0
Income tax expense from reclassification adjustments (included in income tax expense)	(0.1)	1.7	(0.2)
Reclassification adjustment for gains included in net income	0	(5.9)	0.2
Other comprehensive (loss) income	(5.2)	(4.2)	3.8
Comprehensive income	$ 14.1	$ 15.1	$ 16.5