Earnings Per Share - Computation of Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Basic net income per share:
Net (loss) income attributable to InfraREIT, Inc.	$ (26,873)us-gaap_NetIncomeLoss	$ 3,845us-gaap_NetIncomeLoss
Weighted average common shares outstanding	41,204,000	35,053,000
Basic net income per share	$ (0.65)us-gaap_EarningsPerShareBasic	$ 0.11us-gaap_EarningsPerShareBasic
Diluted net income per share:
Net (loss) income attributable to InfraREIT, Inc.	(26,873)us-gaap_NetIncomeLoss	3,845us-gaap_NetIncomeLoss
Weighted average common shares outstanding	41,204,000	35,053,000
Redemption of operating partnership units	0	0
Weighted average dilutive shares outstanding	41,204,000	35,053,000
Diluted net income per share	$ (0.65)us-gaap_EarningsPerShareDiluted	$ 0.11us-gaap_EarningsPerShareDiluted
Due to the anti-dilutive effect, the computation of diluted earnings per share does not reflect the following adjustments:
Net (loss) income attributable to noncontrolling interest	$ (9,000)	$ 1,147
Redemption of operating partnership units	13,801,000	10,421,000

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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