Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Income Statement [Abstract]
Revenues	$ 634,444	$ 574,874
Cost of services	490,640	479,436
Gross profit	143,804	95,438
Selling, general and administrative expenses	85,850	67,768
Contingent consideration	35	69
Loss (gain) on sale of assets	(71)	(13,060)
Operating income (loss)	57,990	40,661
Interest expense	397	1,184
Other (income) expense, net	(1,393)	695
Income (loss) from operations before income taxes	58,986	38,782
Provision for (benefit from) income taxes	15,398	10,028
Net income (loss)	43,588	28,754
Net income attributable to noncontrolling interest	(2,632)	(2,352)
Comprehensive income attributable to IES Holdings, Inc.	$ 40,956	$ 26,402
Earnings Per Share, Basic	$ 1.89	$ 1.15
Earnings Per Share, Diluted	$ 1.87	$ 1.14
Weighted Average Number of Shares Outstanding, Basic	20,199,587	20,242,114
Weighted Average Number of Shares Outstanding, Diluted	20,435,148	20,449,035