Per Share Information EPS (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share Reconciliation [Abstract]
Net income (loss) attributable to common shareholders of IES Holdings, Inc.	$ (29,569)	$ 3,841
Net income attributable to restricted shareholders of IES Holdings, Inc.	0	31
Net Income (loss)	$ (29,569)	$ 3,872
Weighted Average Number of Shares Outstanding, Basic	21,196,854	21,286,090
Effect of dilutive stock options and non-vested restricted stock	0	271,748
Weighted Average Number of Shares Outstanding, Diluted	21,196,854	21,557,838
Earnings (loss) per share attributable to IES Holdings, Inc.:
Earnings (loss) Per Share, Basic	$ (1.39)	$ 0.18
Earnings (loss) Per Share, Diluted	$ (1.39)	$ 0.18