Quarterly Results of Operations (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2012

Quarterly Results of Operations (Tables) [Abstract]

Summary of Unaudited Quarterly Results of Operations

		Year Ended December 31, 2012
		1st Quarter		2nd Quarter		3rd Quarter(2)		4th Quarter
Revenues - as reported		$	435,359	$	453,082	$	474,139	$	500,663
Discontinued operations			(18,817)		(14,778)		(12,306)		(945)
Revenues - as adjusted(1)		$	416,542	$	438,304	$	461,833	$	499,718
Net income (loss) attributable to common stockholders		$	39,307	$	54,735	$	37,269	$	90,576
Net income (loss) attributable to common stockholders per share:
	Basic	$	0.20	$	0.26	$	0.17	$	0.35
	Diluted		0.19		0.25		0.16		0.35
		Year Ended December 31, 2011
		1st Quarter		2nd Quarter		3rd Quarter(3)		4th Quarter(4)
Revenues - as reported		$	255,477	$	381,059	$	384,786	$	407,391
Discontinued operations			(28,362)		(25,863)		(26,114)		(24,360)
Revenues - as adjusted(1)		$	227,115	$	355,196	$	358,672	$	383,031
Net income attributable to common stockholders		$	23,372	$	69,847	$	36,607	$	27,282
Net income attributable to common stockholders per share:
	Basic	$	0.15	$	0.40	$	0.21	$	0.15
	Diluted		0.15		0.39		0.21		0.15
(1) We have reclassified the income attributable to the properties sold prior to or held for sale at September 30, 2013 to discontinued operations. See Note 5.
(2) The decreases in net income and amounts per share are primarily attributable to gains on sales of real estate totaling $32,450,000 for the second quarter as compared to $12,827,000 for the third quarter.
(3) The decreases in net income and amounts per share are primarily attributable to gains on sales of real estate totaling $30,224,000 for the second quarter as compared to $185,000 for the third quarter.
(4) The decreases in net income and amounts per share are primarily attributable to impairment charges of $11,992,000.