Share Incentive Plans (Details) (USD $) In Thousands	12 Months Ended
Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Compensation information
Compensation Expense	$ 18,875	$ 17,843	$ 22,311
Compensation Capitalized	2,141	1,961	2,094
Compensation Equity	21,016	19,804	24,405
Dividends Incurred	1,472	1,881	2,175
Performance Shares [Member]
Compensation information
Compensation Expense		103	(8)
Compensation Capitalized		76
Compensation Equity		179	(8)
Restricted shares [Member]
Compensation information
Compensation Expense	8,603	10,065	15,761
Compensation Capitalized	1,178	1,067	1,517
Compensation Equity	9,781	11,132	17,278
Dividends Incurred	1,334	1,627	2,175
LTIP Units [Member]
Compensation information
Compensation Expense	2,334	1,036
Compensation Capitalized	190	158
Compensation Equity	2,524	1,194
Dividends Incurred	138	254
Share options [Member]
Compensation information
Compensation Expense	6,707	5,458	5,361
Compensation Capitalized	714	538	485
Compensation Equity	7,421	5,996	5,846
ESPP Discount [Member]
Compensation information
Compensation Expense	1,231	1,181	1,197
Compensation Capitalized	59	122	92
Compensation Equity	$ 1,290	$ 1,303	$ 1,289

Share based compensation expense related Disclosure

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Period Type:	duration

- Definition

Represents dividends paid during the period for each type of long term compensation outstanding.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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- Definition

This element represents the amount of recognized share-based compensation during the period, that is, the amount recognized as expense in the income statement (or as asset if compensation is capitalized).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph 39

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph 64
-Subparagraph b

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph A91

+ Details

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- Definition

Represents the expense recognized during the period arising from share-based compensation arrangements (for example, shares of stock, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph 64
-Subparagraph b

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph A240
-Subparagraph g(1)

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 14
-Section F

+ Details

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- Definition

Represents the compensation cost capitalized during the period arising from share-based compensation arrangements (for example, shares of stock, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph A240
-Subparagraph g(1)

+ Details

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