Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid In Capital [Member]	Accumulated Other Comprehensive Income [Member]	Retained Earnings [Member]
Balance at Sep. 30, 2014	$ 87,972	$ 220	$ (2,394)	$ 194,719	$ (2)	$ (104,571)
Balance, shares at Sep. 30, 2014		22,049,529	(281,829)
Restricted stock grant			$ 1,615	(1,615)
Restricted stock grant, shares			207,874
Acquisition of treasury stock	(3,622)		$ (3,622)
Acquisition of treasury stock, shares			(499,833)
Non-cash compensation	524			524
Interest Rate Swap	$ (2)				2
Options Exercised, shares	0
Net Income Attributable to IES Holdings	$ 16,538					16,538
Balance at Sep. 30, 2015	101,414	$ 220	$ (4,401)	193,628	0	(88,033)
Balance, shares at Sep. 30, 2015		22,049,529	(573,788)
Restricted stock grant			$ 44	(44)
Restricted stock grant, shares			5,670
Forfeiture of restricted stock			$ (72)	72
Forfeiture of restricted stock, shares			(7,500)
Acquisition of treasury stock	(590)		$ (685)	95
Acquisition of treasury stock, shares			(59,872)
Non-cash compensation	1,583			1,583
Options Exercised	$ 220		$ 333	(113)
Options Exercised, shares	42,500		42,500
Net Income Attributable to IES Holdings	$ 120,778					120,778
Balance at Sep. 30, 2016	223,405	$ 220	$ (4,781)	195,221	0	32,745
Balance, shares at Sep. 30, 2016		22,049,529	(592,990)
Restricted stock grant			$ 15	(15)
Restricted stock grant, shares			1,803
Forfeiture of restricted stock			$ (40)	40
Forfeiture of restricted stock, shares			2,257
Acquisition of treasury stock	(2,367)		$ (2,367)
Acquisition of treasury stock, shares			(152,860)
Non-cash compensation	1,707			1,707
Interest Rate Swap	0
Options Exercised	$ 218		$ 275	(57)
Options Exercised, shares	33,750		33,750
Net Income Attributable to IES Holdings	$ 13,422					13,422
Balance at Sep. 30, 2017	236,704	$ 220	$ (6,898)	196,955	$ 0	46,427
Balance, shares at Sep. 30, 2017		22,049,529	(712,554)
Cumulative effect of ASU	363			$ 59		304
Increase in noncontrolling interest	$ (44)					$ (44)