Discontinued Operations (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Operating results for the asset held for sale
Rental revenue	$ 46,322	$ 35,570	$ 89,469	$ 71,873
Rental operating expenses	(11,116)	(8,604)	(21,886)	(17,301)
Real estate taxes and insurance	(7,311)	(5,493)	(13,908)	(11,189)
Depreciation and amortization	(17,124)	(13,003)	(33,111)	(26,074)
Net (loss) income from discontinued operations		(268)		(585)
Discontinued operations
Operating results for the asset held for sale
Rental revenue		259		624
Rental operating expenses		(224)		(603)
Real estate taxes and insurance		(82)		(200)
Depreciation and amortization		(221)		(406)
Net (loss) income from discontinued operations		$ (268)		$ (585)

This element represents the total of the costs related to real estate revenues, including management, leasing, and development services.

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- Definition

The current period expense charged against earnings on long-lived, physical assets not used in production, and which are not intended for resale, to allocate or recognize the cost of such assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset; or to reflect consumption during the period of an asset that is not used in production.

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- Definition

After tax income (loss) from operations of a business component (exclusive of any gain (loss) on disposal, or provision therefore) during the reporting period, until its disposal.

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- Definition

The aggregate revenue from real estate operations during the reporting period.

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The aggregate total of real estate taxes and insurance expense.

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