Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Income Statement [Abstract]
Revenues	$ 2,166,808	$ 1,536,493	$ 1,190,856
Cost of services	1,847,878	1,248,495	962,897
Gross profit	318,930	287,998	227,959
Selling, general and administrative expenses	262,714	202,251	170,911
Goodwill impairment expense	0	0	6,976
Contingent consideration	277	211	11
Loss (gain) on sale of assets	(69)	(47)	0
Operating income	56,008	85,583	50,083
Interest expense	2,970	962	777
Other (income) expense, net	37	(286)	12
Income from operations before income taxes	53,001	84,907	49,294
Provision for income taxes	12,815	16,231	8,740
Net income (loss)	40,186	68,676	40,554
Net (income) loss attributable to noncontrolling interest	(5,424)	(2,018)	1,045
Comprehensive income (loss) attributable to IES Holdings, Inc.	$ 34,762	$ 66,658	$ 41,599
Earnings (loss) per share, basic	$ 1.45	$ 3.19	$ 1.96
Earnings (loss) per share, diluted	$ 1.44	$ 3.15	$ 1.94
Weighted Average Number of Shares Outstanding, Basic	20,667,745	20,790,307	20,795,892
Weighted Average Number of Shares Outstanding, Diluted	20,894,625	21,086,432	21,092,410