Taxable Income (Loss) (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
State income tax expense:
Texas gross margins tax	$ 118	$ 108	$ 261	$ 227
Other	29	(126)	(42)	(83)
Total state income tax expense	147	(18)	219	144
State income tax payments, net of refunds (and collections)	$ 523	$ 481	$ 547	$ 503
Taxable Income (Textual) [Abstract]
Condition to qualify as a REIT as defined under the Internal Revenue Code			Company must meet a number of organizational and operational requirements, including a requirement that it distribute at least 90% of its annual taxable income to its stockholders
Taxable income to be distributed to stockholders			90.00%