Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Aug. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Amortization Expense, Remainder of Fiscal Year	$ 3,200	$ 1,200
Other intangible assets			$ 7,761
Below market ground leases			$ 118,050
Finite-Lived Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	49,708
Finite-Lived Intangible Assets, Accumulated Amortization	(3,447)
Finite-Lived Intangible Assets, Net	46,260
Below market ground leases
Finite-Lived Intangible Assets [Line Items]
Below Market Lease, Net	46,260
Below Market Lease, Accumulated Amortization	(3,447)
Below market ground leases	$ 49,708