Federal Income Tax Reporting (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Federal Income Tax Reporting
Maximum ownership as a percentage of the voting power or value of the securities of each issuer other than REIT or "TRS"	10.00%
Maximum ownership of securities in all TRS (as a percent)	20.00%			25.00%
Maximum ownership of securities in all TRS when considered together with other non-real estate assets (as a percent)	25.00%
Gross amount of NOL of TRS	$ 4,600	$ 4,400
Period of statute of limitations applicable to the entity's income tax returns	3 years
Net operating losses
NOLs expiration period	20 years
Gross amount of NOLs available to company	$ 13,000	13,000	$ 13,000
Income Tax Expense
Revised Texas Franchise Tax	250	394	319
Other Taxes		(125)	41
Tax expense	250	269	$ 360
Deferred income taxes	0
Real estate assets net tax basis more (less) than book basis	$ 253,000	$ 195,000

The portion of the difference between total income tax expense or benefit as reported in the income statement for the period and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations attributable to the Revised Texas Franchise Tax.

No definition available.