Leases - Lease Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Leases [Abstract]
Fixed income from operating leases	$ 984,942	$ 1,013,757	$ 944,796
Variable income from operating leases	237,136	223,479	268,853
Interest income from direct financing leases	$ 37,481	$ 54,274	$ 54,217