Lease Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Lease Income
Fixed-lease income	$ 954,966	$ 1,068,701	$ 2,009,920	$ 2,128,820
Variable lease income	58,544	229,866	265,822	449,803
Total lease income	$ 1,013,510	$ 1,298,567	$ 2,275,742	$ 2,578,623