Real Property Acquisitions and Development - Estimated Fair Value of Allocated Purchase Price of Asset and Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Business Acquisition [Line Items]
Land and land improvements	$ 56,605	$ 43,562
Buildings and improvements	304,702	232,546
Acquired lease intangibles	34,633	15,147
Right of use assets, net	0	2,012
Receivables and other assets	396	264
Total assets acquired	396,336	293,531
Secured debt	0	(43,209)
Lease liabilities	0	(961)
Accrued expenses and other liabilities	(2,707)	(2,800)
Total liabilities acquired	(2,707)	(46,970)
Noncontrolling interests	(2,827)	(8,951)
Cash disbursed for acquisitions	390,802	237,610
Construction in progress additions	57,415	57,673
Less: Capitalized interest	(4,746)	(2,327)
Accruals	(3,894)	45
Cash disbursed for construction in progress	48,775	55,391
Capital improvements to existing properties	69,382	56,935
Total cash invested in real property, net of cash acquired	508,959	349,936
Cash acquired from acquisition	580	517
Seniors Housing Operating
Business Acquisition [Line Items]
Land and land improvements	15,758	6,831
Buildings and improvements	132,480	97,759
Acquired lease intangibles	10,810	4,945
Right of use assets, net	0	0
Receivables and other assets	257	264
Total assets acquired	159,305	109,799
Secured debt	0	(43,209)
Lease liabilities	0	0
Accrued expenses and other liabilities	(671)	(848)
Total liabilities acquired	(671)	(44,057)
Noncontrolling interests	(2,827)	(7,895)
Cash disbursed for acquisitions	155,807	57,847
Construction in progress additions	29,841	35,756
Less: Capitalized interest	(2,812)	(1,136)
Accruals	(2,600)	0
Cash disbursed for construction in progress	24,429	34,620
Capital improvements to existing properties	52,503	43,300
Total cash invested in real property, net of cash acquired	232,739	135,767
Triple-net
Business Acquisition [Line Items]
Land and land improvements	0	7,427
Buildings and improvements	765	74,116
Acquired lease intangibles	0	0
Right of use assets, net	0	0
Receivables and other assets	0	0
Total assets acquired	765	81,543
Secured debt	0	0
Lease liabilities	0	0
Accrued expenses and other liabilities	0	0
Total liabilities acquired	0	0
Noncontrolling interests	0	(1,056)
Cash disbursed for acquisitions	765	80,487
Construction in progress additions	13,929	7,442
Less: Capitalized interest	(941)	(390)
Accruals	0	0
Cash disbursed for construction in progress	12,988	7,052
Capital improvements to existing properties	3,248	3,768
Total cash invested in real property, net of cash acquired	17,001	91,307
Outpatient Medical
Business Acquisition [Line Items]
Land and land improvements	40,847	29,304
Buildings and improvements	171,457	60,671
Acquired lease intangibles	23,823	10,202
Right of use assets, net	0	2,012
Receivables and other assets	139	0
Total assets acquired	236,266	102,189
Secured debt	0	0
Lease liabilities	0	(961)
Accrued expenses and other liabilities	(2,036)	(1,952)
Total liabilities acquired	(2,036)	(2,913)
Noncontrolling interests	0	0
Cash disbursed for acquisitions	234,230	99,276
Construction in progress additions	13,645	14,475
Less: Capitalized interest	(993)	(801)
Accruals	(1,294)	45
Cash disbursed for construction in progress	11,358	13,719
Capital improvements to existing properties	13,631	9,867
Total cash invested in real property, net of cash acquired	$ 259,219	$ 122,862