Summary of Significant Accounting Policies (Narrative) (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Jun. 02, 2010
Summary Of Significant Accounting Policies (Textuals) [Abstract]
Development costs for land	$ 7.8
Revenue increased by straight-line rent adjustment	6.3	4.2
Increased revenue due to amortization of deferred rent	0.6	0.6
Decrease in revenue due to amortization of lease incentives	0.4	0.2
Increase in Common shares available for future awards			6,000,000
Increase in shares due to amendments in plan, shares solely available for options and share appreciation rights	3,599,672		3,600,000
Common shares available for future awards	5,272,117
Options awarded, term	one to ten-year
Award vesting term, minimum	1 year
Award vesting term, maximum	10 years
Stock-based compensation expense	1.7	1.6
Stock-based compensation expense, capitalized	0.4	0.3
Distributable income minimum percentage	90.00%
PJP VII [Member]
Variable Interest Entity [Line Items]
Guarantor Obligations, Current Carrying Value	$ 0.7