SEGMENT INFORMATION - Revenue and Net Real Estate Property (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Revenues:
Total revenues	$ 1,017,554	$ 910,291
Net Real Estate Property:
Total net real estate property	21,982,221		$ 21,816,838
United States
Revenues:
Total revenues	897,933	797,768
Net Real Estate Property:
Total net real estate property	18,718,109		18,562,738
Canada
Revenues:
Total revenues	112,144	105,033
Net Real Estate Property:
Total net real estate property	3,027,276		3,007,008
United Kingdom
Revenues:
Total revenues	7,477	$ 7,490
Net Real Estate Property:
Total net real estate property	$ 236,836		$ 247,092