Summary of Significant Accounting Policies (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Accounting Policies [Abstract]
Number of VIEs	4		4
Increase in real estate assets as a result of consolidating the VIEs	$ 72.2		$ 72.2
Building and Improvements
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 22.6	$ 18.9	$ 65.0	$ 55.6