Intangibles - Summary of Carrying Amount of Intangible Assets and Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Assets
Cost	$ 517,338	$ 452,384
Accumulated Amortization	(145,629)	(127,557)
Net	371,709	324,827
Liabilities
Below-market and Above-market ground leases, net	6,903	13,585
Lease liability, cost	61,097	0
Lease liability, accumulated amortization	(405)	0
Lease liability	60,692	0
Cost	75,552	20,619
Accumulated Amortization	(7,957)	(7,034)
Net	67,595	13,585
In-place lease intangibles
Assets
Cost	344,329	340,428
Accumulated Amortization	(128,565)	(111,500)
Net	215,764	228,928
Above-market leases
Assets
Cost	45,516	45,568
Accumulated Amortization	(15,786)	(13,621)
Net	29,730	31,947
Leasehold interest
Assets
Cost	712	712
Accumulated Amortization	(272)	(242)
Net	440	470
Below-market ground leases
Assets
Cost	0	65,676
Accumulated Amortization	0	(2,194)
Net	0	63,482
Right-of-use lease assets
Assets
Cost	126,781	0
Accumulated Amortization	(1,006)	0
Net	125,775	0
Below-market leases
Liabilities
Below-market and Above-market ground leases, cost	14,455	14,654
Below-market and Above-market ground leases, accumulated amortization	(7,552)	(6,768)
Below-market and Above-market ground leases, net	6,903	7,886
Above-market ground leases
Liabilities
Below-market and Above-market ground leases, cost	0	5,965
Below-market and Above-market ground leases, accumulated amortization	0	(266)
Below-market and Above-market ground leases, net	$ 0	$ 5,699