Schedule III: Real Estate and Accumulated Depreciation - Summary Real Estate and Accumulated Depreciation (Details) - AIR Real Estate [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Total portfolio
Total portfolio balance at beginning of year	$ 7,351,979	$ 7,338,906	$ 7,488,019
Additions during the year:
Acquisitions	6,062	81,344	501,009
Capital additions	329,156	368,133	310,452
Dispositions and other	(218,333)	(436,404)	(960,574)
Total portfolio balance at end of year	7,468,864	7,351,979	7,338,906
Accumulated depreciation balance at beginning of year	2,268,839	2,228,533	2,504,193
Depreciation	310,400	308,905	320,664
Dispositions and other	(123,734)	(268,599)	(596,324)
Accumulated depreciation balance at end of year	$ 2,455,505	$ 2,268,839	$ 2,228,533