Leases - Lease Income for Operating Leases (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Fixed lease income		$ 677,060	$ 722,146
Variable lease income		43,588	46,494
Straight-line rent write-off	[1]	(2,850)
Total lease income		$ 717,798	$ 768,640

[1] We monitor the collectability of all unpaid rent amounts. The onset of COVID-19 and the anticipated economic slowdown resulted in a $2.9 million write-off of accrued straight-line rent during the year ended December 31, 2020.