Real Property Acquisitions and Development (Details Textual) (USD $)	May 01, 2012 properties	Mar. 31, 2012
Real Property Acquisitions and Development (Textual) [Abstract]
Cash consideration of capital lease obligation	$ 509,500,000
Number of properties in portfolio	42
Percentage of interest owned by company in partnership		95.00%
Percentage of interest owned by minority	50.00%	5.00%
Liability for Uncertain Tax Positions, Noncurrent		$ 206,000

Amount of cash paid to acquire the entity.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141R

-Paragraph 68

-Subparagraph f(1)

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 51

-Subparagraph d

Name:	us-gaap_BusinessAcquisitionCostOfAcquiredEntityCashPaid
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant