Summary of Significant Accounting Policies Deferred Financing and Leasing Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Deferred Financing and Leasing Costs [Abstract]
Capitalized compensation, leasing costs	$ 4.6	$ 3.9	$ 2.8