Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2015		Sep. 30, 2014		Sep. 30, 2013
Income per common share
Net income	$ 19.1	$ 32.1	$ 30.7	$ 29.5	$ 23.6	$ 32.8	$ 33.0	$ 20.3	$ 111.4	[1]	$ 109.7	[1]	$ 63.4	[1]
Weighted-average shares outstanding-basic (in shares)									63.2		63.2		62.7
Effect of dilutive stock options and unvested time-based restricted stock (in shares)									0.7		0.6		0.3
Weighted average shares outstanding-diluted (in shares)									63.9		63.8		63.0
Earnings per share-basic (in dollars per share)	$ 0.30	$ 0.51	$ 0.49	$ 0.47	$ 0.38	$ 0.52	$ 0.52	$ 0.32	$ 1.76	[1]	$ 1.74	[1]	$ 1.01	[1]
Earnings per share-diluted (in dollars per share)	$ 0.30	$ 0.50	$ 0.48	$ 0.46	$ 0.37	$ 0.51	$ 0.51	$ 0.32	$ 1.74	[1]	$ 1.72	[1]	$ 1.01	[1]
Performance Shares
Income per common share
Shares with anti-dilutive effect excluded from the computation of diluted earnings per share									1.6		1.9		2.1
Stock Option Awards and Time Based Stock Awards
Income per common share
Shares with anti-dilutive effect excluded from the computation of diluted earnings per share									0.7		0.4		1.3

[1] Net income attributable to Hillenbrand