Deferred Costs (Details Textuals) (USD $) In Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Deferred Costs (Textuals) [Abstract]
Capitalized internal direct leasing costs	$ 1.7	$ 1.3	$ 3.2	$ 3.1