Unaudited Quarterly Financial Information (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2019		Sep. 30, 2018		Sep. 30, 2017
Quarterly Financial Information Disclosure [Abstract]
Net revenue	$ 485.8	$ 446.6	$ 464.6	$ 410.3	$ 474.7	$ 446.0	$ 452.2	$ 397.2	$ 1,807.3		$ 1,770.1		$ 1,590.2
Gross profit	166.7	148.4	160.9	147.0	163.8	163.5	168.6	146.2	623.0		642.1		590.8
Net income	$ 24.7	$ 30.4	$ 38.0	$ 28.3	$ 44.5	$ 35.9	$ (21.9)	$ 18.1	$ 121.4	[1]	$ 76.6	[1]	$ 126.2	[1]
Earnings per share-basic (in dollars per share)	$ 0.39	$ 0.48	$ 0.60	$ 0.45	$ 0.71	$ 0.57	$ (0.34)	$ 0.28	$ 1.93	[1]	$ 1.21	[1]	$ 1.99	[1]
Earnings per share-diluted (in dollars per share)	$ 0.39	$ 0.48	$ 0.60	$ 0.45	$ 0.70	$ 0.56	$ (0.34)	$ 0.28	$ 1.92	[1]	$ 1.20	[1]	$ 1.97	[1]

[1] Net income attributable to Hillenbrand