Real Property Acquisitions and Development - Estimated Fair Value of Allocated Purchase Price of Asset and Liabilities (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Business Acquisition [Line Items]
Land and land improvements	$ 358,155	$ 59,010
Buildings and improvements	2,319,285	304,876
Acquired lease intangibles	159,772	34,633
Right of use assets, net	77,455	0
Total net real estate assets	2,914,667	398,519
Receivables and other assets	9,575	396
Total assets acquired	2,924,242	398,915
Lease liabilities	(138,126)	0
Accrued expenses and other liabilities	(29,717)	(2,714)
Total liabilities acquired	(167,843)	(2,714)
Noncontrolling interests	(21,193)	(2,827)
Cash disbursed for acquisitions	2,735,206	393,374
Construction in progress additions	280,371	142,231
Less: Capitalized interest	(14,027)	(13,234)
Accruals	(3,019)	(2,298)
Cash disbursed for construction in progress	263,325	126,699
Capital improvements to existing properties	165,691	183,324
Total cash invested in real property, net of cash acquired	3,164,222	703,397
Cash acquired from acquisition	301	580
Seniors Housing Operating
Business Acquisition [Line Items]
Land and land improvements	264,706	15,758
Buildings and improvements	1,655,067	132,481
Acquired lease intangibles	142,439	10,810
Right of use assets, net	77,455	0
Total net real estate assets	2,139,667	159,049
Receivables and other assets	6,041	257
Total assets acquired	2,145,708	159,306
Lease liabilities	(138,126)	0
Accrued expenses and other liabilities	(20,748)	(671)
Total liabilities acquired	(158,874)	(671)
Noncontrolling interests	(2,597)	(2,827)
Cash disbursed for acquisitions	1,984,237	155,808
Construction in progress additions	190,672	75,617
Less: Capitalized interest	(9,658)	(7,760)
Accruals	38	(1,376)
Cash disbursed for construction in progress	181,052	66,481
Capital improvements to existing properties	115,115	130,465
Total cash invested in real property, net of cash acquired	2,280,404	352,754
Triple-net
Business Acquisition [Line Items]
Land and land improvements	48,099	0
Buildings and improvements	436,828	765
Acquired lease intangibles	0	0
Right of use assets, net	0	0
Total net real estate assets	484,927	765
Receivables and other assets	0	0
Total assets acquired	484,927	765
Lease liabilities	0	0
Accrued expenses and other liabilities	(8,703)	0
Total liabilities acquired	(8,703)	0
Noncontrolling interests	(2,056)	0
Cash disbursed for acquisitions	474,168	765
Construction in progress additions	60,251	33,021
Less: Capitalized interest	(2,092)	(2,569)
Accruals	0	0
Cash disbursed for construction in progress	58,159	30,452
Capital improvements to existing properties	26,496	5,971
Total cash invested in real property, net of cash acquired	558,823	37,188
Outpatient Medical
Business Acquisition [Line Items]
Land and land improvements	45,350	43,252
Buildings and improvements	227,390	171,630
Acquired lease intangibles	17,333	23,823
Right of use assets, net	0	0
Total net real estate assets	290,073	238,705
Receivables and other assets	3,534	139
Total assets acquired	293,607	238,844
Lease liabilities	0	0
Accrued expenses and other liabilities	(266)	(2,043)
Total liabilities acquired	(266)	(2,043)
Noncontrolling interests	(16,540)	0
Cash disbursed for acquisitions	276,801	236,801
Construction in progress additions	29,448	33,593
Less: Capitalized interest	(2,277)	(2,905)
Accruals	(3,057)	(922)
Cash disbursed for construction in progress	24,114	29,766
Capital improvements to existing properties	24,080	46,888
Total cash invested in real property, net of cash acquired	$ 324,995	$ 313,455