Leases - Rental Revenue (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Jul. 27, 2020	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Leases [Abstract]
Cash rent		$ 253,117	$ 277,324	$ 522,702	$ 559,899
Straight-line rent		3,404	8,043	5,458	15,455
Lease intangible amortization		(788)	(611)	(1,536)	(1,342)
Property operating cost reimbursements		1,363	1,422	2,791	2,886
Sub-lease		5,279	5,282	10,543	10,771
Total fixed		262,375	291,460	539,958	587,669
Variable		16,039	20,372	36,852	40,789
Income from direct financing leases		162	211	352	428
Total rental revenue		278,576	$ 312,043	$ 577,162	$ 628,886
Rental Revenue [Member]
Lessor, Lease, Description [Line Items]
Deferral agreements		3,600
Deferral agreements, abated		11,200
COVID-19 effect, excluding straight line rent reserve		4,700
COVID-19 effect, general reserve increase		900
COVID-19 effect, amount not probable For collection		3,800
COVID-19 effect, straight line rent receivable, increase in reserve		$ 3,700
Rental Revenue [Member] | Subsequent Event [Member]
Lessor, Lease, Description [Line Items]
Deferral agreements	$ 5,300