Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Revenues	$ 276,043	$ 243,842
Cost of services	225,828	202,241
Gross profit	50,215	41,601
Selling, general and administrative expenses	37,872	32,086
Contingent consideration	0	34
Loss (gain) on sale of assets	(36)	(3)
Operating income (loss)	12,379	9,484
Interest expense	239	547
Other (income) expense, net	141	47
Income (loss) from operations before income taxes	11,999	8,890
Provision for (benefit from) income taxes	3,469	1,907
Net income (loss)	8,530	6,983
Net income attributable to noncontrolling interest	(28)	(99)
Comprehensive income attributable to IES Holdings, Inc.	$ 8,502	$ 6,884
Earnings Per Share, Basic	$ 0.40	$ 0.32
Earnings Per Share, Diluted	$ 0.39	$ 0.32
Weighted Average Number of Shares Outstanding, Basic	20,883,477	21,233,132
Weighted Average Number of Shares Outstanding, Diluted	21,148,312	21,261,065