Organization and significant policies (Details)	Mar. 31, 2013
Percentage of common stock by subsidiaries of ARL	83.80%
Percentage of common stock of Income Opportunity Realty Investors, Inc. By TCI	81.10%
Number of interests in a total property portfolio of income producing properties	59
Number of commercial buildings	13
Number of office buildings	10
Number of industrial warehouse	1
Number of retails centers	2
Aggregate approximately rentable square feet in millions	3.4
Number of apartment communities	46
Apartment communities units total	8,239
Area of acres of developed and undeveloped land	4,105
Buildings and improvements minimum useful life	10
Buildings and improvements maximum useful life	40
Furniture, fixtures and equipment minimum useful life	5
Furniture, fixtures and equipment maximum useful life	10