Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Balance at beginning of period	$ (72.8)	$ 8.6
Current increase (decrease)	(107.4)	(78.8)
Income tax (expense) benefit	0.9	(2.8)
Balance at end of period	(179.3)	(73.0)
Other comprehensive income (loss) attributable to noncontrolling interests, net of tax	(0.2)	(0.2)
Balance at end of period attributable to Sirona Dental Systems, Inc.	(179.1)	(72.8)
Cumulative translation adjustments
Balance at beginning of period	(85.6)	2.9
Current increase (decrease)	(103.7)	(88.7)
Income tax (expense) benefit	0.0	0.0
Balance at end of period	(189.3)	(85.8)
Other comprehensive income (loss) attributable to noncontrolling interests, net of tax	(0.2)	(0.2)
Balance at end of period attributable to Sirona Dental Systems, Inc.	(189.1)	(85.6)
Unrecognized elements of pension cost
Balance at beginning of period	13.2	6.4
Current increase (decrease)	(4.1)	9.4
Income tax (expense) benefit	1.1	(2.6)
Balance at end of period	10.2	13.2
Balance at end of period attributable to Sirona Dental Systems, Inc.	10.2	13.2
Net gain (loss) from hedging instruments
Balance at beginning of period	(0.4)	(0.7)
Current increase (decrease)	0.4	0.5
Income tax (expense) benefit	(0.2)	(0.2)
Balance at end of period	(0.2)	(0.4)
Balance at end of period attributable to Sirona Dental Systems, Inc.	$ (0.2)	$ (0.4)