CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Performing	$ 123,911	$ 143,601
Allowance for doubtful accounts	17,037	17,037
Deferred revenue from sales to related parties	91,087	91,380
Accounts payable and other liabilities to related parties	$ 48,303	$ 56,303
Series A Preferred stock, par value (in dollars per share)	$ 2.00	$ 2.00
Series A Preferred stock, authorized (in shares)	15,000,000	15,000,000
Series A Preferred stock, issued (in shares)	2,000,614	2,000,614
Series A Preferred stock, outstanding (in shares)	2,000,614	2,000,614
Series A Preferred stock, liquidation preference (in dollars per share)	$ 10	$ 10
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	100,000,000	100,000,000
Common stock, issued (in shares)	15,930,145	14,443,404
Common stock, outstanding (in shares)	15,514,360	14,027,619
Shares held by subsidiaries (in shares)	2,000,614
Treasury stock (in shares)	415,785	415,785
Transcontinential Realty Investors [Member] | Common Stock [Member]
Shares held by subsidiaries (in shares)	140,000	140,000
Treasury stock (in shares)	140,000	140,000
Series A Cumulative Convertible Preferred Stock [Member]
Shares held by subsidiaries (in shares)	900,000	900,000
Related Party [Member]
Performing	$ 99,793	$ 128,548
Allowance for doubtful accounts	15,537	17,037
Deferred revenue from sales to related parties	70,915	70,935
Accounts payable and other liabilities to related parties	$ 10,769	$ 10,854