Secured Debt (Details 2) (USD $) In Thousands	Jun. 30, 2011	Dec. 31, 2010
Aggregate maturities of secured debt
2011	$ 124,635
2012	300,136
2013	108,323
2014	112,720
2015	213,114
Thereafter	1,133,473
Total	1,992,401	1,908,068
Mortgage notes payable [Member] \| Fixed Rate Debt [Member]
Aggregate maturities of secured debt
2011	42,281
2012	61,610
2013	16,511
2014	73,316
2015	193,177
Thereafter	177,234
Total	564,129
Mortgage notes payable [Member] \| Variable Rate Debt [Member]
Aggregate maturities of secured debt
2011	41,430
2012	1,053
2013	53,181
2014	36,076
2015	16,415
Thereafter	29,046
Total	177,201
Tax Exempt Notes Payable [Member] \| Fixed Rate Debt [Member]
Aggregate maturities of secured debt
2011	0
2012	0
2013	0
2014	0
2015	0
Thereafter	0
Total	0
Tax Exempt Notes Payable [Member] \| Variable Rate Debt [Member]
Aggregate maturities of secured debt
2011	0
2012	0
2013	0
2014	0
2015	0
Thereafter	94,700
Total	94,700
Credit Facilities [Member] \| Fixed Rate Debt [Member]
Aggregate maturities of secured debt
2011	1,411
2012	177,944
2013	38,631
2014	3,328
2015	3,522
Thereafter	671,084
Total	895,920
Credit Facilities [Member] \| Variable Rate Debt [Member]
Aggregate maturities of secured debt
2011	39,513
2012	59,529
2013	0
2014	0
2015	0
Thereafter	161,409
Total	260,451
Fixed Rate Debt [Member]
Aggregate maturities of secured debt
Total	1,460,049
Variable Rate Debt [Member]
Aggregate maturities of secured debt
Total	$ 532,352,000

Amount of secured debt maturities after year five following the date of the latest balance sheet presented in the financial statements.

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- Definition

Amount of secured debt maturing within the next twelve months following the date of the latest balance sheet presented in the financial statements.

+ Details

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- Definition

Amount of secured debt maturing in year five following the date of the latest balance sheet presented in the financial statements.

+ Details

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- Definition

Amount of secured debt maturing in year four following the date of the latest balance sheet presented in the financial statements.

+ Details

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- Definition

Amount of secured debt maturing in year three following the date of the latest balance sheet presented in the financial statements.

+ Details

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- Definition

Amount of secured debt maturing in year two following the date of the latest balance sheet presented in the financial statements.

+ Details

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- Details

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- Definition

Carrying value as of the balance sheet date , including the current and noncurrent portions, of collateralized debt obligations (with maturities initially due after one year or beyond the operating cycle, if longer). Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.16)
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 19, 20, 22
-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 16
-Article 9

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.16)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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