Property Dispositions, Assets Held for Sale, and Discontinued Operations (Assets Held-for-Sale) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total other assets held for sale, net	$ 0	$ 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	0	76,614
Straight-line rent receivables	0	4,729
Prepaid expenses and other assets	0	66
Deferred lease costs, less accumulated amortization of $0 and $1,162 as of December 31, 2016 and 2015, respectively	0	3,695
Accumulated amortization on deferred lease costs	0	1,162
Total other assets held for sale, net	0	8,490
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:	0	9,759
Disposal Group, Held-for-sale, Not Discontinued Operations [Member] | Building and building improvements [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Real estate assets held for sale, net:	0	66,840
Accumulated depreciation (building improvements)	0	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:	$ 0	$ 15