Assets Held for Sale (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total other assets held for sale, net	$ 40,036	$ 61,233
Accrued expenses	7,275	8,780
Disposal Group, Held-for-sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Accumulated depreciation (building improvements)	(61,579)	(102,476)
Total real estate assets held for sale, net	213,094	331,068
Straight-line rent receivables	26,132	36,584
Prepaid expenses and other assets	452	1,095
Deferred lease costs, less accumulated amortization of $7,887 and $9,138 as of September 30, 2019 and December 31, 2018, respectively	13,452	23,554
Accumulated amortization on deferred lease costs	(7,887)	(9,138)
Total other assets held for sale, net	40,036	61,233
Accrued expenses	7,275	8,780
Disposal Group, Held-for-sale, Not Discontinued Operations | Land
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Real estate assets held for sale, net:	36,990	67,552
Disposal Group, Held-for-sale, Not Discontinued Operations | Building and building improvements
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Real estate assets held for sale, net:	176,066	261,463
Disposal Group, Held-for-sale, Not Discontinued Operations | Construction in progress
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Real estate assets held for sale, net:	$ 38	$ 2,053