Per Share Information (Tables)

12 Months Ended

Sep. 30, 2020

Earnings Per Share [Abstract]

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

	Year Ended September 30,
	2020		2019		2018
Numerator:
Net income (loss) attributable to common shareholders of IES Holdings, Inc.	$	40,830	$	32,950	$	(14,113)
Increase (decrease) in noncontrolling interest	194		—		(44)
Net income attributable to restricted shareholders of IES Holdings, Inc.	575		256		—
Net income (loss) attributable to IES Holdings, Inc.	$	41,599	$	33,206	$	(14,157)
Denominator:
Weighted average common shares outstanding — basic	20,795,892		21,082,012		21,196,388
Effect of dilutive stock options and non-vested securities	296,518		233,233		—
Weighted average common and common equivalent shares outstanding — diluted	21,092,410		21,315,245		21,196,388
Earnings (loss) per share attributable to common shareholders of IES Holdings, Inc.:
Basic	$	1.96	$	1.56	$	(0.67)
Diluted	$	1.94	$	1.55	$	(0.67)