Combined Guarantor Subsidiaries - Leases - Narrative (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019 USD ($) ground_lease	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($) ground_lease	Sep. 30, 2018 USD ($)
Lessee, Lease, Description [Line Items]
Tenant reimbursements period related to certain capital expenditure minimum			5 years
Tenant reimbursements period related to certain capital expenditure maximum			15 years
Uncollectable operating lease receivables recognized	$ (188)	$ 487	$ 1,504	$ 3,273
Number of ground leases | ground_lease	8		8
Guarantor Subsidiaries
Lessee, Lease, Description [Line Items]
Tenant reimbursements period related to certain capital expenditure minimum			5 years
Tenant reimbursements period related to certain capital expenditure maximum			15 years
Uncollectable operating lease receivables recognized	$ 94	$ 388	$ 1,262	$ 1,154
Number of ground leases | ground_lease	1		1
Operating lease renewal term	5 years		5 years
Lease expense	$ 10		$ 30