Summary of Significant Accounting Policies (Details 3) $ / shares in Units, $ in Millions		3 Months Ended		9 Months Ended
	Sep. 28, 2015 $ / shares	Sep. 30, 2015 USD ($) $ / shares	Sep. 30, 2014 $ / shares	Sep. 30, 2015 USD ($) item buildings $ / shares	Sep. 30, 2014 $ / shares	Dec. 31, 2014 USD ($)
Dividends and Distributions
Cash dividend declared to common shareholders (in dollars per share)	$ 0.225	$ 0.225	$ 0.225	$ 0.675	$ 0.675
Cash dividend distributed to common shareholders (in dollars per share)	$ 0.225
Real Estate Loans Receivable
Number of mezzanine loans collateralized | item				3
Number of medical office building developments as collateral for real estate loans receivable | buildings				1
Rental Revenue
Rental revenue due in excess of amounts currently due from tenants | $		$ 12.8		$ 12.8		$ 6.4