Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Revenues	$ 243,842	$ 198,300
Cost of services	202,241	165,236
Gross profit	41,601	33,064
Selling, general and administrative expenses	32,086	30,089
Contingent consideration	34	0
Gain on sale of assets	(3)	(14)
Operating income	9,484	2,989
Interest and other (income) expense:
Interest expense	547	441
Other income, net	47	(98)
Income from operations before income taxes	8,890	2,646
Provision (Benefit) for income taxes	1,907	32,159
Net Income (loss)	6,983	(29,513)
Net income attributable to noncontrolling interest	(99)	(56)
Comprehensive income (loss) attributable to IES Holdings, Inc.	$ 6,884	$ (29,569)
Earnings (loss) per share attributable to IES Holdings, Inc.:
Basic	$ 0.32	$ (1.39)
Diluted	$ 0.32	$ (1.39)
Shares used in the computation of earnings (loss) per share
Basic	21,233,132	21,196,854
Diluted	21,261,065	21,196,854