Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]
Lease revenue	$ 50,921	$ 41,452	$ 29,458	$ 29,372	$ 45,044	$ 39,309	$ 25,225	$ 24,837	$ 151,203	$ 134,415	$ 73,193
General and administrative expense	(5,641)	(5,504)	(4,728)	(48,733)	(5,786)	(6,143)	(3,284)	(3,412)	(64,606)	(18,625)	(13,691)
Depreciation	(10,773)	(10,259)	(9,671)	(9,508)	(9,255)	(8,998)	(8,366)	(8,461)	(40,211)	(35,080)	(20,024)
Interest expense, net	(7,470)	(6,723)	(6,939)	(7,422)	(8,377)	(8,699)	(7,984)	(7,681)	(28,554)	(32,741)	(17,384)
Other (expense) income, net	868	707	847	626	(17,569)	294	172	(133)	3,048	(17,236)	20,932
Income tax expense	(374)	(243)	(124)	(208)	(297)	(248)	(250)	(158)	(949)	(953)	(616)
Net income	27,531	19,430	8,843	(35,873)	3,760	15,515	5,513	4,992	19,931	29,780	42,410
Less: Net income attributable to noncontrolling interest	7,725	5,458	2,481	(9,000)	836	3,621	1,278	1,147	6,664	6,882	10,288
Net income attributable to InfraREIT, Inc.	$ 19,806	$ 13,972	$ 6,362	$ (26,873)	$ 2,924	$ 11,894	$ 4,235	$ 3,845	$ 13,267	$ 22,898	$ 32,122
Basic EPS	$ 0.45	$ 0.32	$ 0.15	$ (0.65)	$ 0.08	$ 0.34	$ 0.12	$ 0.11	$ 0.31	$ 0.65	$ 1.07
Diluted EPS	$ 0.45	$ 0.32	$ 0.15	$ (0.65)	$ 0.08	$ 0.34	$ 0.12	$ 0.11	$ 0.31	$ 0.65	$ 1.07