Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Valuation Allowance [Line Items]
Date of commencement to be taxable as REIT			Dec. 31, 2004
Minimum percentage of taxable income to be qualify as REIT			90.00%
Inability to Qualify Period			4 years
Income tax examination years under examination			2008 through 2011
Income and other taxes, continuing operations	$ 75,000	$ 85,000	$ 218,000	$ 385,000
United Kingdom [Member]
Valuation Allowance [Line Items]
Statutory rate charged by United Kingdom for taxing real property operating results			22.00%
Deferred tax assets generated by United Kingdom taxable losses	1,126,000		1,126,000
Full valuation allowance on deferred tax assets	$ (1,126,000)		$ (1,126,000)