Per Share Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Earnings Per Share [Abstract]
Undistributed Earnings (Loss) Available to Common Shareholders, Basic	$ 38,174	$ 23,336
Noncontrolling Interest, Change in Redemption Value	(2,782)	(3,055)
Undistributed Earnings (Loss) Allocated to Participating Securities, Basic	0	(11)
Net income (loss) attributable to IES Holdings, Inc.	$ 40,956	$ 26,402
Weighted Average Number of Shares Outstanding, Basic	20,199,587	20,242,114
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	235,561	206,921
Weighted Average Number of Shares Outstanding, Diluted	20,435,148	20,449,035
Earnings Per Share, Basic	$ 1.89	$ 1.15
Earnings Per Share, Diluted	$ 1.87	$ 1.14
Phantom Share Units (PSUs) [Member]
Earnings Per Share [Abstract]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	64,500	60,212
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	64,500	60,212