Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Revenue	$ 4,057,088	$ 4,531,426	$ 4,747,116
Private pay
Disaggregation of Revenue [Line Items]
Revenue	2,572,426	2,809,903
Government reimbursement
Disaggregation of Revenue [Line Items]
Revenue	509,037	522,209
Other third-party payor programs
Disaggregation of Revenue [Line Items]
Revenue	128,468	117,099
Resident fees
Disaggregation of Revenue [Line Items]
Revenue	3,209,931	3,449,211
Independent Living | Private pay
Disaggregation of Revenue [Line Items]
Revenue	542,112	596,852
Independent Living | Government reimbursement
Disaggregation of Revenue [Line Items]
Revenue	2,446	3,125
Independent Living | Other third-party payor programs
Disaggregation of Revenue [Line Items]
Revenue	0	0
Independent Living | Resident fees
Disaggregation of Revenue [Line Items]
Revenue	544,558	599,977
Assisted Living and Memory Care | Private pay
Disaggregation of Revenue [Line Items]
Revenue	1,748,364	1,923,676
Assisted Living and Memory Care | Government reimbursement
Disaggregation of Revenue [Line Items]
Revenue	67,574	72,175
Assisted Living and Memory Care | Other third-party payor programs
Disaggregation of Revenue [Line Items]
Revenue	0	0
Assisted Living and Memory Care | Resident fees
Disaggregation of Revenue [Line Items]
Revenue	1,815,938	1,995,851
CCRCs | Private pay
Disaggregation of Revenue [Line Items]
Revenue	281,197	288,682
CCRCs | Government reimbursement
Disaggregation of Revenue [Line Items]
Revenue	81,054	87,028
CCRCs | Other third-party payor programs
Disaggregation of Revenue [Line Items]
Revenue	39,924	40,698
CCRCs | Resident fees
Disaggregation of Revenue [Line Items]
Revenue	402,175	416,408
Health Care Services | Private pay
Disaggregation of Revenue [Line Items]
Revenue	753	693
Health Care Services | Government reimbursement
Disaggregation of Revenue [Line Items]
Revenue	357,963	359,881
Health Care Services | Other third-party payor programs
Disaggregation of Revenue [Line Items]
Revenue	88,544	76,401
Health Care Services | Resident fees
Disaggregation of Revenue [Line Items]
Revenue	$ 447,260	$ 436,975