Strategic Transformation and Restructuring, Impairment and Other Asset Charges - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Sep. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Restructuring Cost and Reserve [Line Items]
Restructuring, impairment and other asset charges, net			$ 2.5	$ 8.1	$ 3.2
Restructuring reserve			1.2	1.1
Assets held for sale			5.1	6.3
Gain (loss) on disposition of property plant equipment			0.6	6.2	(0.3)
Disposal group, including discontinued operation, consideration				6.9
Other restructuring charges			0.0	0.3	0.0
Disposal group, accounts payable, current				1.1
(Price adjustment on prior) proceeds from sale of subsidiary		$ 0.5
Astec Mobile Machinery GmbH
Restructuring Cost and Reserve [Line Items]
Assets held for sale				0.3
Gain (loss) on disposition of property plant equipment		$ 0.7
Costs associated with closing Enid
Restructuring Cost and Reserve [Line Items]
Assets held for sale				5.1
Facility Closing | Costs associated with closing Albuquerque
Restructuring Cost and Reserve [Line Items]
Assets held for sale					2.8
Gain (loss) on disposition of property plant equipment	$ 0.4
Disposal group, including discontinued operation, consideration	3.2
Business exit costs			0.0	1.3	0.0
Facility Closing | Costs associated with closing Enid
Restructuring Cost and Reserve [Line Items]
Disposal group, including discontinued operation, consideration	$ 1.1
Other restructuring charges			0.7
Business exit costs			0.7	2.5	0.0
Facility Closing | Costs associated with closing Mequon
Restructuring Cost and Reserve [Line Items]
Gain (loss) on disposition of property plant equipment				4.7
Disposal group, including discontinued operation, consideration				8.5
Other restructuring charges			0.6
Business exit costs			0.6	3.3	0.0
Facility Closing | Costs associated with closing Tacoma
Restructuring Cost and Reserve [Line Items]
Gain (loss) on disposition of property plant equipment			1.6
Business exit costs			1.6	$ 0.9	$ 0.0
Strategic Transformation
Restructuring Cost and Reserve [Line Items]
Restructuring costs			$ 13.4