Property Dispositions, Assets Held for Sale, and Discontinued Operations (Schedule of Assets Held for Sale) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Other assets held for sale, net	$ 8,761	$ 8,490
Disposal Group, Held-for-sale, Not Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total real estate assets held for sale, net	69,766	76,614
Straight-line rent receivables	5,109	4,729
Prepaid expenses and other assets	36	66
Deferred lease costs, less accumulated amortization of $1,429 and $1,162 as of June 30, 2016 and December 31, 2015, respectively	3,616	3,695
Other assets held for sale, net	8,761	8,490
Accumulated amortization on deferred lease costs	1,429	1,162
Disposal Group, Held-for-sale, Not Discontinued Operations [Member] | Land [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Real estate assets held for sale, net:	9,759	9,759
Disposal Group, Held-for-sale, Not Discontinued Operations [Member] | Building and improvements Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Real estate assets held for sale, net:	59,998	66,840
Accumulated depreciation and amortization	33,336	32,162
Disposal Group, Held-for-sale, Not Discontinued Operations [Member] | Construction in progress [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Real estate assets held for sale, net:	$ 9	$ 15