Condensed Consolidating Information - Consolidating balance sheet (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018	Oct. 01, 2018	Sep. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017
ASSETS
Cash and cash equivalents	$ 58.6			$ 56.0	$ 68.5
Trade receivables, net	199.5			218.5
Receivables from long-term manufacturing contracts	164.8		$ 122.2	120.3
Inventories	183.0		170.9	172.5
Prepaid expense	24.1			25.2
Other current assets	20.4			18.1
Total current assets	650.4			610.6
Property, plant, and equipment, net	137.6			142.0
Intangible assets, net	477.3			487.3
Goodwill	583.0			581.9
Investment in consolidated subsidiaries	0.0
Other assets	37.2			42.8
Total Assets	1,885.5			1,864.6
LIABILITIES
Trade accounts payable	207.7			196.8
Liabilities from long-term manufacturing contracts and advances	125.1			125.9
Accrued compensation	55.5			71.9
Other current liabilities	117.5			137.1
Total current liabilities	505.8			531.7
Long-term debt	361.7			344.6
Accrued pension and postretirement healthcare	114.6			120.5
Deferred income taxes	79.4		$ 76.5	76.4
Other long-term liabilities	53.9			47.3
Total Liabilities	1,115.4			1,120.5
Hillenbrand Shareholders’ Equity	756.8			731.1
Stockholders' Equity Attributable to Parent [Abstract]
Noncontrolling interests	13.3			13.0
Total Shareholders’ Equity	770.1	$ 747.4		744.1	$ 732.0	$ 768.5	$ 765.9
Total Liabilities and Equity	1,885.5			1,864.6
Reportable legal entities | Parent
ASSETS
Cash and cash equivalents	0.2			1.1
Prepaid expense	2.9			2.7
Intercompany receivables	0.0			0.0
Other current assets	0.0			0.0
Total current assets	3.1			3.8
Property, plant, and equipment, net	3.6			3.8
Intangible assets, net	2.8			3.2
Investment in consolidated subsidiaries	2,290.8			2,263.1
Other assets	27.1			15.7
Total Assets	2,327.4			2,289.6
LIABILITIES
Trade accounts payable	0.2			0.0
Accrued compensation	3.9			7.2
Intercompany payables	1,176.6			1,206.2
Other current liabilities	22.8			19.4
Total current liabilities	1,203.5			1,232.8
Long-term debt	333.6			300.2
Accrued pension and postretirement healthcare	0.7			0.7
Deferred income taxes	0.0			0.7
Other long-term liabilities	32.8			24.1
Total Liabilities	1,570.6			1,558.5
Hillenbrand Shareholders’ Equity	756.8			731.1
Stockholders' Equity Attributable to Parent [Abstract]
Total Shareholders’ Equity	756.8			731.1
Total Liabilities and Equity	2,327.4			2,289.6
Reportable legal entities | Guarantors
ASSETS
Cash and cash equivalents	5.3			5.8
Trade receivables, net	105.7			124.5
Receivables from long-term manufacturing contracts	8.4			5.3
Inventories	82.9			76.7
Prepaid expense	7.7			7.0
Intercompany receivables	1,130.9			1,131.1
Other current assets	1.9			3.2
Total current assets	1,342.8			1,353.6
Property, plant, and equipment, net	58.9			60.2
Intangible assets, net	188.6			196.0
Goodwill	225.0			225.0
Investment in consolidated subsidiaries	668.0			653.9
Other assets	26.5			28.2
Total Assets	2,509.8			2,516.9
LIABILITIES
Trade accounts payable	62.9			62.4
Liabilities from long-term manufacturing contracts and advances	24.6			26.6
Accrued compensation	13.6			20.1
Intercompany payables	6.3			6.1
Other current liabilities	47.4			38.9
Total current liabilities	154.8			154.1
Accrued pension and postretirement healthcare	29.1			29.8
Deferred income taxes	26.6			22.9
Other long-term liabilities	12.5			14.3
Total Liabilities	223.0			221.1
Hillenbrand Shareholders’ Equity	2,286.8			2,295.8
Stockholders' Equity Attributable to Parent [Abstract]
Total Shareholders’ Equity	2,286.8			2,295.8
Total Liabilities and Equity	2,509.8			2,516.9
Reportable legal entities | Non-Guarantors
ASSETS
Cash and cash equivalents	53.1			49.1
Trade receivables, net	93.8			94.0
Receivables from long-term manufacturing contracts	156.4			115.0
Inventories	103.0			98.6
Prepaid expense	13.5			15.5
Intercompany receivables	49.1			79.1
Other current assets	18.1			14.6
Total current assets	487.0			465.9
Property, plant, and equipment, net	75.1			78.0
Intangible assets, net	285.9			288.1
Goodwill	358.0			356.9
Investment in consolidated subsidiaries	0.0
Other assets	1.9			5.9
Total Assets	1,207.9			1,194.8
LIABILITIES
Trade accounts payable	144.6			134.4
Liabilities from long-term manufacturing contracts and advances	100.5			99.3
Accrued compensation	38.0			44.6
Other current liabilities	58.3			78.1
Total current liabilities	341.4			356.4
Long-term debt	28.1			44.4
Accrued pension and postretirement healthcare	84.8			90.0
Deferred income taxes	59.7			60.9
Other long-term liabilities	8.6			8.9
Total Liabilities	522.6			560.6
Hillenbrand Shareholders’ Equity	672.0			621.2
Stockholders' Equity Attributable to Parent [Abstract]
Noncontrolling interests	13.3			13.0
Total Shareholders’ Equity	685.3			634.2
Total Liabilities and Equity	1,207.9			1,194.8
Consolidation, Eliminations [Member]
ASSETS
Inventories	(2.9)			(2.8)
Intercompany receivables	(1,180.0)			(1,210.2)
Other current assets	0.4			0.3
Total current assets	(1,182.5)			(1,212.7)
Investment in consolidated subsidiaries	(2,958.8)			(2,917.0)
Other assets	(18.3)			(7.0)
Total Assets	(4,159.6)			(4,136.7)
LIABILITIES
Trade accounts payable	0.0			0.0
Intercompany payables	(1,182.9)			(1,212.3)
Other current liabilities	(11.0)			0.7
Total current liabilities	(1,193.9)			(1,211.6)
Deferred income taxes	(6.9)			(8.1)
Other long-term liabilities	0.0
Total Liabilities	(1,200.8)			(1,219.7)
Hillenbrand Shareholders’ Equity	(2,958.8)			(2,917.0)
Stockholders' Equity Attributable to Parent [Abstract]
Total Shareholders’ Equity	(2,958.8)			(2,917.0)
Total Liabilities and Equity	$ (4,159.6)			$ (4,136.7)