Segment Reporting - Segment Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Segment Reporting Information, Additional Information
Assets	$ 2,296,201	$ 2,209,446
Net Lease
Segment Reporting Information, Additional Information
Assets	1,537,643	1,453,148
Self Storage
Segment Reporting Information, Additional Information
Assets	406,343	410,781
Multi-family
Segment Reporting Information, Additional Information
Assets	260,193	230,509
All Other
Segment Reporting Information, Additional Information
Assets	66,913	66,936
Corporate
Segment Reporting Information, Additional Information
Assets	$ 25,109	$ 48,072