Earnings Per Share - Computation of Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Basic net income per share:
Net income (loss) attributable to InfraREIT, Inc.	$ 6,608	$ 6,362	$ 12,923	$ (20,511)
Weighted average common shares outstanding	43,576	43,565	43,573	42,391
Basic net income (loss) per share	$ 0.15	$ 0.15	$ 0.30	$ (0.48)
Diluted net income per share:
Net income (loss) attributable to InfraREIT, Inc.	$ 6,608	$ 6,362	$ 12,923	$ (20,511)
Weighted average common shares outstanding	43,576	43,565	43,573	42,391
Weighted average dilutive shares outstanding	43,576	43,565	43,573	42,391
Diluted net income (loss) per share	$ 0.15	$ 0.15	$ 0.30	$ (0.48)
Due to the anti-dilutive effect, the computation of diluted earnings per share does not reflect the following adjustments:
Net income (loss) attributable to noncontrolling interest	$ 2,576	$ 2,481	$ 5,038	$ (6,519)
Redemption of operating partnership units	17,058	17,028	17,057	15,424