Condensed Consolidating Information - Consolidating balance sheet (Details) - USD ($) $ in Millions	Dec. 31, 2018	Oct. 01, 2018	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
ASSETS
Cash and cash equivalents	$ 64.8		$ 56.0	$ 77.8
Trade receivables, net	190.5		218.5
Receivables from long-term manufacturing contracts	134.2	$ 122.2	120.3
Inventories	182.3	170.9	172.5
Prepaid expense	24.5		25.2
Other current assets	17.1		18.1
Total current assets	613.4		610.6
Property, plant, and equipment, net	140.2		142.0
Intangible assets, net	490.6		487.3
Goodwill	587.3		581.9
Other assets	38.7		42.8
Total Assets	1,870.2		1,864.6
LIABILITIES
Trade accounts payable	196.0		196.8
Liabilities from long-term manufacturing contracts and advances	135.8		125.9
Current portion of long-term debt	0.0		0.0
Accrued compensation	53.5		71.9
Other current liabilities	125.2		137.1
Total current liabilities	510.5		531.7
Long-term debt	364.8		344.6
Accrued pension and postretirement healthcare	117.8		120.5
Deferred income taxes	77.7	$ 76.5	76.4
Other long-term liabilities	52.0		47.3
Total Liabilities	1,122.8		1,120.5
Hillenbrand Shareholders’ Equity	734.5		731.1
Stockholders' Equity Attributable to Parent [Abstract]
Noncontrolling interests	12.9		13.0
Total Shareholders’ Equity	747.4		744.1	$ 768.5	$ 765.9
Total Liabilities and Equity	1,870.2		1,864.6
Reportable legal entities | Parent
ASSETS
Cash and cash equivalents	0.4		1.1
Prepaid expense	3.4		2.7
Intercompany receivables	0.0		0.0
Other current assets	0.0		0.0
Total current assets	3.8		3.8
Property, plant, and equipment, net	3.8		3.8
Intangible assets, net	2.9		3.2
Investment in consolidated subsidiaries	2,331.9		2,263.1
Other assets	29.9		15.7
Total Assets	2,372.3		2,289.6
LIABILITIES
Trade accounts payable	2.0		0.0
Current portion of long-term debt	0.0		0.0
Accrued compensation	2.1		7.2
Intercompany payables	1,249.6		1,206.2
Other current liabilities	21.0		19.4
Total current liabilities	1,274.7		1,232.8
Long-term debt	334.0		300.2
Accrued pension and postretirement healthcare	0.7		0.7
Deferred income taxes	0.0		0.7
Other long-term liabilities	28.4		24.1
Total Liabilities	1,637.8		1,558.5
Hillenbrand Shareholders’ Equity	734.5		731.1
Stockholders' Equity Attributable to Parent [Abstract]
Total Shareholders’ Equity	734.5		731.1
Total Liabilities and Equity	2,372.3		2,289.6
Reportable legal entities | Guarantors
ASSETS
Cash and cash equivalents	4.2		5.8
Trade receivables, net	109.4		124.5
Receivables from long-term manufacturing contracts	6.4		5.3
Inventories	83.3		76.7
Prepaid expense	7.2		7.0
Intercompany receivables	1,196.5		1,131.1
Other current assets	2.6		3.2
Total current assets	1,409.6		1,353.6
Property, plant, and equipment, net	59.7		60.2
Intangible assets, net	192.4		196.0
Goodwill	225.0		225.0
Investment in consolidated subsidiaries	668.0		653.9
Other assets	26.7		28.2
Total Assets	2,581.4		2,516.9
LIABILITIES
Trade accounts payable	60.6		62.4
Liabilities from long-term manufacturing contracts and advances	31.2		26.6
Accrued compensation	14.8		20.1
Intercompany payables	4.2		6.1
Other current liabilities	52.8		38.9
Total current liabilities	163.6		154.1
Accrued pension and postretirement healthcare	29.4		29.8
Deferred income taxes	25.5		22.9
Other long-term liabilities	14.7		14.3
Total Liabilities	233.2		221.1
Hillenbrand Shareholders’ Equity	2,348.2		2,295.8
Stockholders' Equity Attributable to Parent [Abstract]
Total Shareholders’ Equity	2,348.2		2,295.8
Total Liabilities and Equity	2,581.4		2,516.9
Reportable legal entities | Non-Guarantors
ASSETS
Cash and cash equivalents	60.2		49.1
Trade receivables, net	81.1		94.0
Receivables from long-term manufacturing contracts	127.8		115.0
Inventories	102.0		98.6
Prepaid expense	13.9		15.5
Intercompany receivables	54.3		79.1
Other current assets	14.1		14.6
Total current assets	453.4		465.9
Property, plant, and equipment, net	76.7		78.0
Intangible assets, net	295.3		288.1
Goodwill	362.3		356.9
Other assets	2.4		5.9
Total Assets	1,190.1		1,194.8
LIABILITIES
Trade accounts payable	133.4		134.4
Liabilities from long-term manufacturing contracts and advances	104.6		99.3
Current portion of long-term debt	0.0		0.0
Accrued compensation	36.6		44.6
Other current liabilities	63.6		78.1
Total current liabilities	338.2		356.4
Long-term debt	30.8		44.4
Accrued pension and postretirement healthcare	87.7		90.0
Deferred income taxes	59.9		60.9
Other long-term liabilities	8.9		8.9
Total Liabilities	525.5		560.6
Hillenbrand Shareholders’ Equity	651.7		621.2
Stockholders' Equity Attributable to Parent [Abstract]
Noncontrolling interests	12.9		13.0
Total Shareholders’ Equity	664.6		634.2
Total Liabilities and Equity	1,190.1		1,194.8
Consolidation, Eliminations [Member]
ASSETS
Inventories	(3.0)		(2.8)
Intercompany receivables	(1,250.8)		(1,210.2)
Other current assets	0.4		0.3
Total current assets	(1,253.4)		(1,212.7)
Investment in consolidated subsidiaries	(2,999.9)		(2,917.0)
Other assets	(20.3)		(7.0)
Total Assets	(4,273.6)		(4,136.7)
LIABILITIES
Trade accounts payable	0.0		0.0
Intercompany payables	(1,253.8)		(1,212.3)
Other current liabilities	(12.2)		0.7
Total current liabilities	(1,266.0)		(1,211.6)
Deferred income taxes	(7.7)		(8.1)
Other long-term liabilities	0.0
Total Liabilities	(1,273.7)		(1,219.7)
Hillenbrand Shareholders’ Equity	(2,999.9)		(2,917.0)
Stockholders' Equity Attributable to Parent [Abstract]
Total Shareholders’ Equity	(2,999.9)		(2,917.0)
Total Liabilities and Equity	$ (4,273.6)		$ (4,136.7)