Organization (Narrative) (Details) $ / shares in Units, ft² in Millions, $ in Billions	Jun. 30, 2016 USD ($) ft² property $ / shares	Dec. 31, 2015 $ / shares	Apr. 04, 2013 $ / shares shares
Operations [Line Items]
Number of real estate properties | property	459
Purchase price | $	$ 2.2
Area of real estate property | ft²	13.3
Percentage of property leased	100.00%
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01
Common Stock
Operations [Line Items]
Shares available in IPO (in shares) | shares			68,000,000.0
Share Price (in dollars per share)			$ 25.00