Quarterly Financial Statement Information (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2011

Quarterly Financial Statement Information [Abstract]

Schedule Of Quarterly Financial Information

	2011
	First		Second		Third		Fourth
Total revenue	$	141,398	$	140,687	$	144,621	$	153,267
Net income attributable to common stockholders		7,224		8,195		8,508		13,929
Basic earnings per share data:
Net income attributable to common stockholders		0.19		0.21		0.20		0.29
Diluted earnings per share data:
Net income attributable to common stockholders		0.19		0.20		0.20		0.29
	2010
	First		Second		Third		Fourth
Total revenue	$	125,867	$	124,946	$	128,627	$	137,139
Net income attributable to common stockholders		2,637		5,168		5,507		6,769
Basic earnings per share data:
Net income attributable to common stockholders		0.08		0.14		0.15		0.18
Diluted earnings per share data:
Net income attributable to common stockholders		0.07		0.14		0.15		0.18