Properties, net (Tables)

12 Months Ended

Dec. 31, 2011

Properties, net

Schedule of components of net operating properties

	December 31,
	2011			2010
Land	$	472,483		$	501,210
Buildings and improvements		2,801,252			2,804,595
Less: accumulated depreciation		(559,679	)		(503,032	)
Operating properties, net	$	2,714,056		$	2,802,773

Schedule of projects in development or held for future development

	December 31,
	2011		2010
Land	$	229,833	$	256,487
Construction in progress, excluding land		409,086		386,195
Projects in development or held for future development	$	638,919	$	642,682

Schedule of operating property dispositions

Project Name	Location	Date of Sale	Number of Buildings		Total Rentable Square Feet		Sale Price		Gain on Sale
1344 & 1348 Ashton Road and 1350 Dorsey Road	Hanover, Maryland	5/24/2011		3		39,000	$	3,800	$	150
216 Schilling Circle	Hunt Valley, Maryland	8/23/2011		1		36,000		4,700		175
Towson Portfolio	Towson, Maryland	9/29/2011		4		179,000		16,000		1,134
11011 McCormick Road	Hunt Valley, Maryland	11/1/2011		1		57,000		3,450		822
10001 Franklin Square Drive	White Marsh, Maryland	12/13/2011		1		218,000		16,250		305
Rutherford Business Center Portfolio	Woodlawn, Maryland	12/15/2011		13		365,000		32,460		2,221
				23		894,000	$	76,660	$	4,807

Schedule of impairment losses recognized in 2011 by period of recognition and by property classification

	Three Months Ended
	3/31/2011		6/30/2011		12/31/2011		Total
Non-operating properties	$	27,742	$	13,574	$	39,193	$	80,509
Operating properties		—		31,031		39,481		70,512
Total	$	27,742	$	44,605	$	78,674	$	151,021

2011 Acquisition

Acquisitions

Schedule of allocation of acquisition costs of property

Land, operating properties	$	261
Building and improvements		26,577
Intangible assets on real estate acquisitions		6,575
Total assets	$	33,413

Schedule of allocation of intangible assets on acquisition of property

			Weighted Average Amortization Period (in Years)
Tenant relationship value	$	3,187		8
In-place lease value		2,904		3
Above-market leases		484		3
	$	6,575		6

2010 Acquisitions

Acquisitions

Schedule of allocation of acquisition costs of property

Land, operating properties	$	13,265
Land, development		5,545
Building and improvements		173,589
Construction in progress		85,525
Intangible assets on real estate acquisitions		42,896
Total assets		320,820
Below-market leases		(231	)
Total acquisition cost	$	320,589

Schedule of allocation of intangible assets on acquisition of property

			Weighted Average Amortization Period (in Years)
In-place lease value	$	21,616		4
Tenant relationship value		14,450		10
Above-market cost arrangements		6,193		40
Above-market leases		637		2
	$	42,896		11