Rental Income and Future Minimum Rent - Allocation of Rental Income (Details) - USD ($) $ in Thousands		12 Months Ended
	Jan. 01, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Leases [Abstract]
Fixed lease payments		$ 786,860	$ 708,362
Variable lease payments		124,443	115,915
Net collectability (reversals) recoveries		(18,997)	2,195
Total rental income		892,306	$ 826,472	$ 656,631
Write-off or revenue, as a result of the COVID-19 pandemic		18,400
Allowance for doubtful accounts, as a result of the COVID-19 pandemic		$ 600
Net collectability (reversals), transitioned to a cash basis of reporting	$ 2,200