Summary of Quarterly Financial Data (Tables)

12 Months Ended

Dec. 31, 2011

Quarterly Financial Information Disclosure [Abstract]

Schedule of Quarterly Financial Information [Table Text Block]

The following table sets forth selected Quarterly Financial Data for the Company on a historical basis for each of the years ended December 31, 2011 and 2010 and has been derived from the accompanying consolidated financial statements as reclassified for discontinued operations (in thousands except per share and per unit data):

2011:		First		Second		Third		Fourth
		Quarter		Quarter		Quarter		Quarter
Operating Data:
Revenues as originally reported	$	127,114		128,382		125,747		125,322
Reclassified to discontinued operations		(2,217	)	(2,459	)	(1,472	)	—
Adjusted Revenues	$	124,897		125,923		124,275		125,322
Net income (loss) attributable to common stockholders	$	2,185		12,861		8,510		8,139
Net income (loss) of limited partners		13		37		27		26
Net income (loss) attributable to common unit holders	$	2,198		12,898		8,537		8,165
Net income (loss) attributable to common stock and   unit holders per share and unit:
Basic	$	0.02		0.14		0.09		0.10
Diluted	$	0.02		0.14		0.09		0.10
2010:
Operating Data:
Revenues as originally reported	$	124,368		121,600		121,410		119,901
Reclassified to discontinued operations		(2,531	)	(4,077	)	(2,193	)	(2,317	)
Adjusted Revenues	$	121,837		117,523		119,217		117,584
Net income (loss) attributable to common stockholders	$	11,399		7,748		7,894		(37,900	)
Net income (loss) of limited partners		94		27		34		(71	)
Net income (loss) attributable to common unit holders	$	11,493		7,775		7,928		(37,971	)
Net income (loss) attributable to common stock and   unit holders per share and unit:
Basic	$	0.14		0.09		0.10		(0.47	)
Diluted	$	0.14		0.09		0.09		(0.46	)