Condensed Consolidated Statement of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Condensed Consolidated Statement of Other Comprehensive Income (Loss) [Abstract]
Net income	$ 8.8	$ 9.4
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustment	(5.6)	(0.3)
Pension liabilities adjustment	(0.2)	0.0
Net unrealized gain or loss on available-for-sale securities	0.0	1.1
Reclassification of adjustments included in net income [Abstract]
Periodic pension costs (included in compensation and benefits)	0.4	0.0
Reclassification adjustment for gains included in net income	0.4	0.0
Other comprehensive income (loss)	(5.4)	0.8
Comprehensive income	$ 3.4	$ 10.2