Accumulated Other Comprehensive Loss - Changes in Accumulated Other Comprehensive Loss (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2014 USD ($)
Accumulated Other Comprehensive Income Loss [Line Items]
Other comprehensive loss before reclassifications	$ (49)
Amounts reclassified from accumulated other comprehensive loss	893
Net period other comprehensive loss	844
Accumulated Other Comprehensive Loss Attributable to InfraREIT, Inc.
Accumulated Other Comprehensive Income Loss [Line Items]
Other comprehensive loss before reclassifications	(77)
Amounts reclassified from accumulated other comprehensive loss	687
Net period other comprehensive loss	610
Accumulated Other Comprehensive Loss Attributable To Noncontrolling Interest
Accumulated Other Comprehensive Income Loss [Line Items]
Other comprehensive loss before reclassifications	28
Amounts reclassified from accumulated other comprehensive loss	206
Net period other comprehensive loss	$ 234