Income Taxes - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating Loss Carryforwards [Line Items]
Income tax benefit, continuing operations, government grants		$ 9.5
Valuation allowance, provision	$ 0.6	1.5	$ 5.8
Valuation allowance, deferred tax asset, decrease, amount	(8.1)
Undistributed earnings of foreign subsidiaries	52.2
Unrecognized tax benefits	10.8	9.7	$ 5.7	$ 2.1
Unrecognized tax benefits, if recognized that would effect the effective rate	11.9	$ 10.5
Astec Brazil | Subsidiaries
Operating Loss Carryforwards [Line Items]
Valuation Allowance, Release	3.4
Astec Germany | Subsidiaries
Operating Loss Carryforwards [Line Items]
Valuation Allowance, Release	3.8
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	235.4
Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	13.0
Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	$ 0.0