Segment Information (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 USD ($) segment	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment									5
Revenue									$ 4,057,088	$ 4,531,426	$ 4,747,116
Segment Operating Income									876,544	1,067,869	1,253,830
General and administrative (including non-cash stock-based compensation expense)									219,289	259,475	278,019
Facility operating lease expense										303,294	339,721
Depreciation and amortization									379,433	447,455	482,077
Goodwill and asset impairment	$ 43,012	$ 2,094	$ 3,769	$ 391	$ 37,927	$ 5,500	$ 16,103	$ 430,363	49,266	489,893	409,782
Loss (gain) on facility lease termination and modification, net	(1,382)	0	(1,797)	(209)	(13,197)	(2,337)	(146,467)	0	3,388	162,001	14,276
Income (loss) from operations	(43,148)	$ (20,222)	$ 2,211	$ 16,661	(46,455)	$ 3,626	$ (137,589)	$ (413,831)	(44,498)	(594,249)	(270,045)
Total interest expense									248,341	280,269	326,154
Total capital expenditures for property, plant and equipment, and leasehold intangibles									295,201	220,810	221,476
Assets	7,194,433				6,467,260				7,194,433	6,467,260
Operating segments | Independent Living
Segment Reporting Information [Line Items]
Revenue									544,558	599,977	654,196
Segment Operating Income									203,741	240,609	271,417
Facility operating lease expense									81,680	93,496	117,131
Depreciation and amortization									81,745	91,899	95,226
Goodwill and asset impairment									1,812	2,013	2,968
Total interest expense									46,713	58,783	55,436
Total capital expenditures for property, plant and equipment, and leasehold intangibles									78,831	51,510	47,309
Assets	1,441,652				1,104,774				1,441,652	1,104,774
Operating segments | Assisted Living and Memory Care
Segment Reporting Information [Line Items]
Revenue									1,815,938	1,995,851	2,210,688
Segment Operating Income									518,636	628,982	749,058
Facility operating lease expense									157,823	178,716	185,971
Depreciation and amortization									222,574	261,365	290,344
Goodwill and asset impairment									32,229	436,892	342,788
Total interest expense									166,097	174,459	207,861
Total capital expenditures for property, plant and equipment, and leasehold intangibles									157,845	125,750	119,717
Assets	4,157,610				3,684,170				4,157,610	3,684,170
Operating segments | CCRCs
Segment Reporting Information [Line Items]
Revenue									402,175	416,408	468,994
Segment Operating Income									72,072	92,212	106,162
Facility operating lease expense									24,248	24,856	29,464
Depreciation and amortization									44,163	53,551	44,294
Goodwill and asset impairment									4,983	6,669	18,083
Total interest expense									27,426	26,746	27,665
Total capital expenditures for property, plant and equipment, and leasehold intangibles									33,535	26,615	24,297
Assets	742,809				707,819				742,809	707,819
Operating segments | Health Care Services
Segment Reporting Information [Line Items]
Revenue									447,260	436,975	446,262
Segment Operating Income									24,987	34,080	51,348
Depreciation and amortization									2,247	3,201	3,723
Goodwill and asset impairment									7,578	9,055	14,599
Total interest expense									0	0	892
Total capital expenditures for property, plant and equipment, and leasehold intangibles									484	902	755
Assets	256,715				254,950				256,715	254,950
Operating segments | Corporate and Management Services
Segment Reporting Information [Line Items]
Revenue									847,157	1,082,215	966,976
Segment Operating Income									57,108	71,986	75,845
Facility operating lease expense									5,915	6,226	7,155
Depreciation and amortization									28,704	37,439	48,490
Goodwill and asset impairment									2,664	35,264	31,344
Total interest expense									8,105	20,281	34,300
Total capital expenditures for property, plant and equipment, and leasehold intangibles									24,506	16,033	$ 29,398
Assets	$ 595,647				$ 715,547				$ 595,647	$ 715,547