Segment Reporting - Summary Information for Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Segment Reporting Information [Line Items]
Resident fees and services	$ 1,971,044	$ 1,393,473	$ 3,835,574	$ 2,753,747
Rental income	483,040	335,811	944,607	753,463
Interest income	62,057	63,453	124,547	116,117
Other income	32,103	32,147	66,603	61,298
Total revenues	2,548,244	1,824,884	4,971,331	3,684,625
Property operating expenses	1,514,711	1,111,297	2,977,101	2,208,210
Consolidated net operating income (loss)	1,033,533	713,587	1,994,230	1,476,415
Depreciation and amortization	495,036	382,045	980,905	747,908
Interest expense	141,157	133,424	286,119	280,742
General and administrative expenses	64,175	55,565	127,933	108,883
Loss (gain) on derivatives and financial instruments, net	(409)	(5,825)	(3,619)	(8,879)
Loss (gain) on extinguishment of debt, net	0	1,705	6,156	1,711
Provision for loan losses, net	(1,113)	5,163	(3,120)	6,177
Impairment of assets	19,876	2,394	72,278	45,725
Other expenses	16,598	48,684	30,658	62,815
Income (loss) from continuing operations before income taxes and other items	298,213	90,432	496,920	231,333
Income tax (expense) benefit	(1,053)	(1,101)	4,466	(7,292)
Income (loss) from unconsolidated entities	(7,392)	4,896	(6,129)	(2,887)
Gain (loss) on real estate dispositions and acquisitions of controlling interests, net	14,850	166,443	66,627	171,150
Income (loss) from continuing operations	304,618	260,670	561,884	392,304
Net income (loss)	304,618	260,670	561,884	392,304
Seniors Housing Operating
Segment Reporting Information [Line Items]
Rental income			381,566	265,959
Operating Segments | Seniors Housing Operating
Segment Reporting Information [Line Items]
Resident fees and services	1,971,044	1,393,473	3,835,574	2,753,747
Rental income	0	0	0	0
Interest income	0	0	0	0
Other income	4,688	1,900	8,029	3,363
Total revenues	1,975,732	1,395,373	3,843,603	2,757,110
Property operating expenses	1,438,277	1,034,906	2,822,961	2,054,253
Consolidated net operating income (loss)	537,455	360,467	1,020,642	702,857
Operating Segments | Triple-net
Segment Reporting Information [Line Items]
Resident fees and services	0	0	0	0
Rental income	273,394	141,151	526,082	362,895
Interest income	0	0	2,111	0
Other income	360	931	591	2,130
Total revenues	273,754	142,082	528,784	365,025
Property operating expenses	8,652	10,495	17,470	21,312
Consolidated net operating income (loss)	265,102	131,587	511,314	343,713
Operating Segments | Outpatient Medical
Segment Reporting Information [Line Items]
Resident fees and services	0	0	0	0
Rental income	209,646	194,660	418,525	390,568
Interest income	0	0	0	0
Other income	2,165	2,577	4,302	4,979
Total revenues	211,811	197,237	422,827	395,547
Property operating expenses	62,834	61,185	127,440	123,648
Consolidated net operating income (loss)	148,977	136,052	295,387	271,899
Non-segment/Corporate
Segment Reporting Information [Line Items]
Resident fees and services	0	0	0	0
Rental income	0	0	0	0
Interest income	62,057	63,453	122,436	116,117
Other income	24,890	26,739	53,681	50,826
Total revenues	86,947	90,192	176,117	166,943
Property operating expenses	4,948	4,711	9,230	8,997
Consolidated net operating income (loss)	$ 81,999	$ 85,481	$ 166,887	$ 157,946