Real Estate Properties - Balance Sheet Information for Disposal of Property (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets of discontinued operations	$ 12,538	$ 12,541
Liabilities of discontinued operations	52	45
Discontinued Operations, Held-for-sale | Discontinued operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Real estate properties, net	12,260	12,260
Other assets	278	281
Assets of discontinued operations	12,538	12,541
Other liabilities	52	45
Liabilities of discontinued operations	$ 52	$ 45