Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Revenues	$ 314,838	$ 276,043
Cost of services	256,159	225,828
Gross profit	58,679	50,215
Selling, general and administrative expenses	42,786	37,872
Loss (gain) on sale of assets	(10)	(36)
Operating income (loss)	15,903	12,379
Interest expense	172	239
Other (income) expense, net	(118)	141
Income (loss) from operations before income taxes	15,849	11,999
Provision for (benefit from) income taxes	3,639	3,469
Net income (loss)	12,210	8,530
Net income attributable to noncontrolling interest	(112)	(28)
Comprehensive income attributable to IES Holdings, Inc.	$ 12,098	$ 8,502
Earnings Per Share, Basic	$ 0.58	$ 0.40
Earnings Per Share, Diluted	$ 0.58	$ 0.39
Weighted Average Number of Shares Outstanding, Basic	20,734,516	20,883,477
Weighted Average Number of Shares Outstanding, Diluted	21,061,355	21,148,312