CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Shareholders AlerisLife Inc	Total Equity Attributable to Common Shareholders	Total Equity Attributable to Common Shareholders Shareholders AlerisLife Inc	Common Shares	Additional Paid In Capital	Cumulative Net Income	Cumulative Distributions	Cumulative Distributions Shareholders AlerisLife Inc	Total Equity Attributable to Noncontrolling Interest
Balance at Dec. 31, 2019	$ 2,877,050		$ 2,736,519		$ 2,379	$ 4,612,511	$ 2,052,562	$ (3,930,933)		$ 140,531
Balance (in shares) at Dec. 31, 2019					237,897,163
Increase (Decrease) in Shareholders' Equity
Net (loss) income	(134,307)		(139,453)				(139,453)			5,146
Distributions	(42,825)	$ (59,801)	(42,825)	$ (59,801)				(42,825)	$ (59,801)
Share grants	1,574		1,574		$ 4	1,570
Share grants (in shares)					420,000
Share repurchases	(171)		(171)			(171)
Share repurchases (in shares)					(47,375)
Share forfeitures	(6)		(6)			(6)
Share forfeitures (in shares)					(1,310)
Distributions to noncontrolling interest	(22,292)									(22,292)
Balance at Dec. 31, 2020	2,619,222		2,495,837		$ 2,383	4,613,904	1,913,109	(4,033,559)		123,385
Balance (in shares) at Dec. 31, 2020					238,268,478
Increase (Decrease) in Shareholders' Equity
Net (loss) income	179,926		174,515				174,515			5,411
Distributions	(9,540)		(9,540)					(9,540)
Share grants	1,964		1,964		$ 8	1,956
Share grants (in shares)					838,000
Share repurchases	(383)		(383)		$ (1)	(382)
Share repurchases (in shares)					(109,384)
Share forfeitures	(3)		(3)			(3)
Share forfeitures (in shares)					(2,200)
Distributions to noncontrolling interest	(22,348)									(22,348)
Sale of interest in joint venture	(106,448)									(106,448)
Balance at Dec. 31, 2021	$ 2,662,390		2,662,390		$ 2,390	4,615,475	2,087,624	(4,043,099)		0
Balance (in shares) at Dec. 31, 2021	238,994,894				238,994,894
Increase (Decrease) in Shareholders' Equity
Net (loss) income	$ (15,774)		(15,774)				(15,774)
Distributions	(9,568)		(9,568)					(9,568)
Share grants	1,745		1,745		$ 8	1,737
Share grants (in shares)					847,000
Share repurchases	(171)		(171)		$ (1)	(170)
Share repurchases (in shares)					(133,752)
Share forfeitures	(11)		(11)			(11)
Share forfeitures (in shares)					(13,300)
Balance at Dec. 31, 2022	$ 2,638,611		$ 2,638,611		$ 2,397	$ 4,617,031	$ 2,071,850	$ (4,052,667)		$ 0
Balance (in shares) at Dec. 31, 2022	239,694,842				239,694,842