Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]
Stockholders' Equity Attributable to Parent at Sep. 30, 2017	$ 236,704	$ 220	$ 6,898	$ 196,955	$ 46,427
Shares, Issued at Sep. 30, 2017		22,049,529	712,554
Restricted stock grant			$ 5	(5)
Restricted stock grant, shares			520
Acquisition of treasury stock	(2,059)		$ (2,059)
Acquisition of treasury stock, shares			(133,459)
Options exercised	11		$ 15	(4)
Options exercised, shares			1,500
Non-cash compensation	(395)			(395)
Decrease in noncontrolling interest	44				44
Net income (loss) attributable to IES Holdings, Inc.	(18,832)				(18,832)
Stockholders' Equity Attributable to Parent at Jun. 30, 2018	215,473	$ 220	$ 8,937	196,551	27,639
Shares, Issued at Jun. 30, 2018		22,049,529	843,993
Stockholders' Equity Attributable to Parent at Mar. 31, 2018	208,070	$ 220	$ 8,108	196,835	19,123
Shares, Issued at Mar. 31, 2018		22,049,529	790,351
Acquisition of treasury stock	(829)		$ (829)
Acquisition of treasury stock, shares			(53,642)
Non-cash compensation	(284)			(284)
Net income (loss) attributable to IES Holdings, Inc.	8,516				8,516
Stockholders' Equity Attributable to Parent at Jun. 30, 2018	215,473	$ 220	$ 8,937	196,551	27,639
Shares, Issued at Jun. 30, 2018		22,049,529	843,993
Stockholders' Equity Attributable to Parent at Sep. 30, 2018	220,407	$ 220	$ 8,937	196,810	32,314
Shares, Issued at Sep. 30, 2018		22,049,529	843,993
Issuances under compensation plans			$ 2,323	(2,323)
Issuances under compensation plans, shares			216,679
Restricted stock grant			$ 3,582	(3,582)
Restricted stock grant, shares			283,195
Cumulative effect adjustment from adoption of new accounting standard	102				102
Acquisition of treasury stock	(8,325)		$ (8,325)
Acquisition of treasury stock, shares			(486,556)
Non-cash compensation	1,484			1,484
Decrease in noncontrolling interest	0
Net income (loss) attributable to IES Holdings, Inc.	23,345				23,345
Stockholders' Equity Attributable to Parent at Jun. 30, 2019	237,013	$ 220	$ 11,357	192,389	55,761
Shares, Issued at Jun. 30, 2019		22,049,529	830,675
Stockholders' Equity Attributable to Parent at Mar. 31, 2019	228,145	$ 220	$ 8,443	191,579	44,789
Shares, Issued at Mar. 31, 2019		22,049,529	667,682
Acquisition of treasury stock	(2,914)		$ (2,914)
Acquisition of treasury stock, shares			(162,993)
Non-cash compensation	810			810
Net income (loss) attributable to IES Holdings, Inc.	10,972				10,972
Stockholders' Equity Attributable to Parent at Jun. 30, 2019	$ 237,013	$ 220	$ 11,357	$ 192,389	$ 55,761
Shares, Issued at Jun. 30, 2019		22,049,529	830,675