Per Share Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	6 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Earnings Per Share [Abstract]
Undistributed Earnings (Loss) Available to Common Shareholders, Basic	$ 6,175	$ 5,467	$ 14,510	$ 12,348
Noncontrolling Interest, Change in Redemption Value	45			0
Undistributed Earnings (Loss) Allocated to Participating Securities, Basic	101	22	223	25
Comprehensive income attributable to IES Holdings, Inc.	$ 6,231	$ 5,489	$ 14,733	$ 12,373
Weighted Average Number of Shares Outstanding, Basic	20,847,245	21,139,096	20,865,460	21,187,834
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	275,065	240,650	267,059	236,688
Weighted Average Number of Shares Outstanding, Diluted	21,122,310	21,379,746	21,132,519	21,424,522
Earnings Per Share, Basic	$ 0.30	$ 0.26	$ 0.70	$ 0.58
Earnings Per Share, Diluted	$ 0.29	$ 0.26	$ 0.69	$ 0.58

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The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

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Change in noncontrolling interest during the period as a result of a change in the redemption value of redeemable noncontrolling interest.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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