Property Investments (Details) $ in Thousands	Dec. 31, 2019 USD ($) property	Dec. 31, 2018 USD ($)
Summary of Company's investment
NUMBER of properties | property	204
Number of real estate investments | property	204
Land	$ 314,398
Buildings, improvements and lease intangibles	3,986,326	$ 3,675,415
Buildings, Improvements, and Lease Intangibles, including Construction in Progress	4,035,057
Personal property	10,538	10,696
Total real estate properties	4,359,993	3,974,071
Total real estate investments	4,359,993
Accumulated Depreciation	(1,121,102)	$ (1,015,174)
Memphis Redevelopment [Member]
Summary of Company's investment
Land	5,222
Buildings, improvements and lease intangibles	3,810
Personal property	0
Total real estate properties	9,032
Accumulated Depreciation	$ (50)
Land Held for Development [Member]
Summary of Company's investment
NUMBER of properties | property	0
Land	$ 24,647
Buildings, improvements and lease intangibles	0
Personal property	0
Total real estate properties	24,647
Accumulated Depreciation	(671)
Construction in Progress [Member]
Summary of Company's investment
Land	0
Buildings, improvements and lease intangibles	48,731
Personal property	0
Total real estate properties	48,731
Accumulated Depreciation	$ 0
Corporate Property [Member]
Summary of Company's investment
NUMBER of properties | property	0
Land	$ 0
Buildings, improvements and lease intangibles	0
Personal property	5,500
Total real estate properties	5,500
Accumulated Depreciation	$ (4,686)
Medical office/outpatient [Member]
Summary of Company's investment
NUMBER of properties | property	204
Land	$ 284,529
Buildings, improvements and lease intangibles	3,982,516
Personal property	5,038
Total real estate properties	4,272,083
Accumulated Depreciation	$ (1,115,695)
Medical office/outpatient [Member] | Washington [Member]
Summary of Company's investment
NUMBER of properties | property	25
Land	$ 58,565
Buildings, improvements and lease intangibles	532,767
Personal property	421
Total real estate properties	591,753
Accumulated Depreciation	$ (88,890)
Medical office/outpatient [Member] | Dallas, Texas [Member]
Summary of Company's investment
NUMBER of properties | property	25
Land	$ 19,194
Buildings, improvements and lease intangibles	496,683
Personal property	442
Total real estate properties	516,319
Accumulated Depreciation	$ (181,556)
Medical office/outpatient [Member] | Los Angeles, California [Member]
Summary of Company's investment
NUMBER of properties | property	14
Land	$ 44,386
Buildings, improvements and lease intangibles	205,829
Personal property	347
Total real estate properties	250,562
Accumulated Depreciation	$ (95,979)
Medical office/outpatient [Member] | Georgia [Member]
Summary of Company's investment
NUMBER of properties | property	9
Land	$ 3,679
Buildings, improvements and lease intangibles	212,509
Personal property	84
Total real estate properties	216,272
Accumulated Depreciation	$ (20,040)
Medical office/outpatient [Member] | Nashville, Tennessee [Member]
Summary of Company's investment
NUMBER of properties | property	6
Land	$ 20,053
Buildings, improvements and lease intangibles	180,463
Personal property	1,109
Total real estate properties	201,625
Accumulated Depreciation	$ (64,038)
Medical office/outpatient [Member] | North Carolina [Member]
Summary of Company's investment
NUMBER of properties | property	16
Land	$ 4,200
Buildings, improvements and lease intangibles	176,261
Personal property	105
Total real estate properties	180,566
Accumulated Depreciation	$ (67,040)
Medical office/outpatient [Member] | Colorado [Member]
Summary of Company's investment
NUMBER of properties | property	9
Land	$ 16,514
Buildings, improvements and lease intangibles	134,004
Personal property	271
Total real estate properties	150,789
Accumulated Depreciation	$ (25,265)
Medical office/outpatient [Member] | Washington, D.C. [Member]
Summary of Company's investment
NUMBER of properties | property	6
Land	$ 0
Buildings, improvements and lease intangibles	150,304
Personal property	21
Total real estate properties	150,325
Accumulated Depreciation	$ (25,097)
Medical office/outpatient [Member] | Virginia [Member]
Summary of Company's investment
NUMBER of properties | property	7
Land	$ 0
Buildings, improvements and lease intangibles	149,132
Personal property	106
Total real estate properties	149,238
Accumulated Depreciation	$ (44,204)
Medical office/outpatient [Member] | Houston, Texas [Member]
Summary of Company's investment
NUMBER of properties | property	9
Land	$ 16,211
Buildings, improvements and lease intangibles	132,013
Personal property	78
Total real estate properties	148,302
Accumulated Depreciation	$ (44,229)
Medical office/outpatient [Member] | Hawaii [Member]
Summary of Company's investment
NUMBER of properties | property	3
Land	$ 8,327
Buildings, improvements and lease intangibles	135,641
Personal property	159
Total real estate properties	144,127
Accumulated Depreciation	$ (39,165)
Medical office/outpatient [Member] | Iowa [Member]
Summary of Company's investment
NUMBER of properties | property	7
Land	$ 12,665
Buildings, improvements and lease intangibles	126,401
Personal property	99
Total real estate properties	139,165
Accumulated Depreciation	$ (34,725)
Medical office/outpatient [Member] | Oklahoma [Member]
Summary of Company's investment
NUMBER of properties | property	4
Land	$ 10,401
Buildings, improvements and lease intangibles	115,706
Personal property	15
Total real estate properties	126,122
Accumulated Depreciation	$ (19,351)
Medical office/outpatient [Member] | Indiana [Member]
Summary of Company's investment
NUMBER of properties | property	4
Land	$ 3,299
Buildings, improvements and lease intangibles	118,847
Personal property	0
Total real estate properties	122,146
Accumulated Depreciation	$ (26,082)
Medical office/outpatient [Member] | San Francisco, California [Member]
Summary of Company's investment
NUMBER of properties | property	3
Land	$ 14,054
Buildings, improvements and lease intangibles	107,396
Personal property	43
Total real estate properties	121,493
Accumulated Depreciation	$ (20,906)
Medical office/outpatient [Member] | Missouri [Member]
Summary of Company's investment
NUMBER of properties | property	1
Land	$ 1,989
Buildings, improvements and lease intangibles	109,304
Personal property	0
Total real estate properties	111,293
Accumulated Depreciation	$ (17,740)
Medical office/outpatient [Member] | Austin, Texas [Member]
Summary of Company's investment
NUMBER of properties | property	5
Land	$ 14,236
Buildings, improvements and lease intangibles	92,809
Personal property	123
Total real estate properties	107,168
Accumulated Depreciation	$ (24,048)
Medical office/outpatient [Member] | Memphis, Tennessee [Member]
Summary of Company's investment
NUMBER of properties | property	7
Land	$ 5,241
Buildings, improvements and lease intangibles	92,508
Personal property	194
Total real estate properties	97,943
Accumulated Depreciation	$ (37,582)
Medical office/outpatient [Member] | San Antonio, Texas [Member]
Summary of Company's investment
NUMBER of properties | property	6
Land	$ 6,487
Buildings, improvements and lease intangibles	88,583
Personal property	404
Total real estate properties	95,474
Accumulated Depreciation	$ (40,573)
Medical office/outpatient [Member] | Illinois [Member]
Summary of Company's investment
NUMBER of properties | property	3
Land	$ 5,859
Buildings, improvements and lease intangibles	87,588
Personal property	211
Total real estate properties	93,658
Accumulated Depreciation	$ (23,540)
Medical office/outpatient [Member] | Minnesota [Member]
Summary of Company's investment
NUMBER of properties | property	4
Land	$ 2,090
Buildings, improvements and lease intangibles	62,359
Personal property	0
Total real estate properties	64,449
Accumulated Depreciation	$ (10,486)
Medical office/outpatient [Member] | Other (16 markets) [Member]
Summary of Company's investment
NUMBER of properties | property	31
Land	$ 17,079
Buildings, improvements and lease intangibles	475,409
Personal property	806
Total real estate properties	493,294
Accumulated Depreciation	$ (165,159)