ACCOUNTING FOR THE IMPAIRMENT OR DISPOSAL OF LONG-LIVED ASSETS

The operating results and gain on disposition of real estate for properties sold and held for sale are reflected in the consolidated statements of operations as discontinued operations. Prior period financial statements have been adjusted for discontinued operations. The proceeds from dispositions of operating properties with no continuing involvement were $365.2 million, $29.0 million and $165.6 million for the years ended December 31, 2011, 2010 and 2009, respectively.

A summary of the results of operations for the properties held for sale and disposed of through the respective disposition dates is as follows (in thousands):



	For the Year Ended
	December 31, 2011			December 31, 2010			December 31, 2009
Revenues	$	58,145		$	93,456		$	115,486
Operating expenses	(25,694		)	(38,313		)	(41,882		)
Interest expense	(9,028		)	(15,320		)	(17,767		)
Depreciation and amortization	(13,166		)	(23,307		)	(25,230		)
Income before property dispositions	10,257			16,516			30,607
Gain on property dispositions	60,582			6,857			17,859
Net income	$	70,839		$	23,373		$	48,466

As of December 31, 2011, seven properties totaling 544,000 square feet in the Company's Northeast-Other reportable segment, 18 properties totaling 1.0 million square feet in the Company's Central reportable segment and 17 properties totaling 1.0 million square feet in the Company's South reportable segment were considered to be held for sale.

Interest expense is allocated to discontinued operations. The allocation of interest expense to discontinued operations was based on the ratio of net assets sold and held for sale to the sum of total net assets plus consolidated debt.

Asset Impairment

During the years ended December 31, 2011, 2010 and 2009, the Company recognized impairment losses of $7.8 million, $1.0 million and $9.5 million, respectively. The 2009 amount excludes $94.5 million in impairment charges recognized in 2009 related to investments in unconsolidated joint ventures and goodwill. See Note 2. The impairment losses are for operating properties or land parcels and were in the reportable segments and for the amounts as indicated below (amounts in thousands):



	Year Ended December 31,
Reportable Segment	2011				2010				2009
Southeastern PA	$	—			$	(52	)	⁽¹⁾	$	—
Lehigh/Central PA	—				—				113
Northeast - Other	538				—				1,138
Central	5,990				511				837
South	1,331				121				4,284
Metro	(30		)	⁽¹⁾	377				3,137
Total	$	7,829			$	957			$	9,509

(1) Represents recovery of estimated sales costs on properties sold.

Impairment losses of $3.2 million were recognized in the fourth quarter of 2011.

For the year ended December 31, 2011, $7.9 million in impairments related to properties sold were included in the caption discontinued operations in the Company's consolidated statement of operations. For the year ended December 31, 2010, $579,000 in impairments related to properties sold were included in the caption discontinued operations in the Company's consolidated statements of operations and $378,000 in impairment was included in the caption impairment charges - investment in unconsolidated joint ventures and other in the Company's consolidated statements of operations. For the year ended December 31, 2009, $5.8 million in impairment related to properties sold was included in the caption discontinued operations in the Company's statement of operations and $3.7 million in impairment was included in the caption impairment charges - investment in unconsolidated joint ventures and other in the Company's consolidated statements of operations. The Company determined these impairments through a comparison of the aggregate future cash flows (including quoted offer prices) to be generated by the properties to the carrying value of the properties. The Company has evaluated each of the properties and land held for development and has determined that there are no additional valuation adjustments necessary at December 31, 2011.