Deferred Costs Deferred Costs (Details Textuals) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Deferred Costs (Textuals) [Abstract]
Capitalized Internal Direct Leasing Costs	$ 1.6	$ 1.4	$ 3.2	$ 2.7