Contingent Matters (Details) - USD ($) $ in Thousands	3 Months Ended		29 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	May 31, 2018
Contingent Matters [Abstract]
Liability recorded related to guarantees	$ 962
Guarantor Obligations [Line Items]
Contingent liability for customer debt	3,366
Revenues from sales contract	$ 325,453	$ 318,401
Testing period of plant production output	30 days
Pellet Plant [Member]
Guarantor Obligations [Line Items]
Revenues from sales contract			$ 142,487
Minimum [Member]
Guarantor Obligations [Line Items]
Period in which testing period may be extended	120 days
Maximum [Member]
Guarantor Obligations [Line Items]
Period in which testing period may be extended	180 days
Letter of Credit Wells Fargo [Member]
Guarantor Obligations [Line Items]
Contingent liabilities for letters of credit	$ 9,400
Letter of credit expiration date	Oct. 31, 2020
Astec Brazil Working Capital Loans [Member]
Guarantor Obligations [Line Items]
Contingent liabilities for letters of credit issued on behalf of foreign subsidiaries	$ 3,200
Letter of Credit [Member]
Guarantor Obligations [Line Items]
Performance bank guarantee, subsidiary obligations to fulfill contracts	6,188
Letter of Credit [Member] | Maximum [Member]
Guarantor Obligations [Line Items]
Contingent liabilities for letters of credit	$ 15,588