Deferred Costs (Details Textuals) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Deferred Costs (Textuals) [Abstract]
Capitalized internal direct leasing costs	$ 1.3	$ 1.4	$ 4.0	$ 4.7