Basis of Presentation Basis of Presentation - Narratives (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($) vie	Mar. 31, 2018 USD ($)	Jan. 01, 2019 USD ($)	Dec. 31, 2018 USD ($) vie
Variable Interest Entity
Variable interest entities, count | vie	22			21
Variable interest entities consolidated, count | vie	21			20
Variable interest entities unconsolidated, count | vie	1			1
Equity investment in real estate	$ 18,316			$ 18,764
Operating lease, right of use asset	36,226
Operating lease liabilities — ground leases	9,409
Lease revenues — net-leased	30,914	$ 32,797
ASU 2016-02
Variable Interest Entity
Cumulative-effect adjustment for the adoption of new accounting pronouncements			$ (1,108)
Operating lease, right of use asset			36,700
Operating lease liabilities — ground leases			9,500
Reclassification of below market intangible assets, above market intangible liabilities, prepaid rent and deferred rent			$ (27,200)
Lease revenues — net-leased	(800)
Equity method investments
Variable Interest Entity
Equity investment in real estate	$ 18,300			$ 18,800