Property Investments (Details) $ in Thousands	Dec. 31, 2018 USD ($) property	Dec. 31, 2017 USD ($)
Summary of Company's investment
Number of facilities | property	199
Number of real estate investments | property	199
Land	$ 254,853
Buildings, Improvements,and Lease Intangibles	3,675,415	$ 3,601,460
Buildings, Improvements, and Lease Intangibles, including Construction in Progress	3,708,522
Personal Property	10,696	10,314
Total real estate properties	3,974,071	3,838,638
Accumulated Depreciation	(1,015,174)	$ (897,430)
Total real estate investments	3,974,071
Wholly Owned Properties [Member]
Summary of Company's investment
Accumulated Depreciation	$ (1,015,174)
Land Held for Development [Member]
Summary of Company's investment
Number of facilities | property	0
Land	$ 24,647
Buildings, Improvements,and Lease Intangibles	0
Personal Property	0
Total real estate properties	24,647
Accumulated Depreciation	(393)
Construction in Progress [Member]
Summary of Company's investment
Land	0
Buildings, Improvements,and Lease Intangibles	33,107
Personal Property	0
Total real estate properties	33,107
Accumulated Depreciation	$ 0
Corporate Property [Member]
Summary of Company's investment
Number of facilities | property	0
Land	$ 0
Buildings, Improvements,and Lease Intangibles
Personal Property	5,500
Total real estate properties	5,500
Accumulated Depreciation	$ (4,467)
Medical office/outpatient [Member]
Summary of Company's investment
Number of facilities | property	199
Land	$ 230,206
Buildings, Improvements,and Lease Intangibles	3,675,415
Personal Property	5,196
Total real estate properties	3,910,817
Accumulated Depreciation	$ (1,010,314)
Medical office/outpatient [Member] | Dallas, Texas [Member]
Summary of Company's investment
Number of facilities | property	25
Land	$ 16,911
Buildings, Improvements,and Lease Intangibles	464,077
Personal Property	430
Total real estate properties	481,418
Accumulated Depreciation	$ (166,980)
Medical office/outpatient [Member] | Washington [Member]
Summary of Company's investment
Number of facilities | property	19
Land	$ 28,867
Buildings, Improvements,and Lease Intangibles	438,880
Personal Property	419
Total real estate properties	468,166
Accumulated Depreciation	$ (69,148)
Medical office/outpatient [Member] | Nashville, Tennessee [Member]
Summary of Company's investment
Number of facilities | property	6
Land	$ 20,053
Buildings, Improvements,and Lease Intangibles	176,257
Personal Property	1,041
Total real estate properties	197,351
Accumulated Depreciation	$ (53,052)
Medical office/outpatient [Member] | Georgia [Member]
Summary of Company's investment
Number of facilities | property	8
Land	$ 1,015
Buildings, Improvements,and Lease Intangibles	189,167
Personal Property	37
Total real estate properties	190,219
Accumulated Depreciation	$ (11,547)
Medical office/outpatient [Member] | Los Angeles, California [Member]
Summary of Company's investment
Number of facilities | property	12
Land	$ 27,709
Buildings, Improvements,and Lease Intangibles	157,496
Personal Property	316
Total real estate properties	185,521
Accumulated Depreciation	$ (87,678)
Medical office/outpatient [Member] | North Carolina [Member]
Summary of Company's investment
Number of facilities | property	16
Land	$ 4,200
Buildings, Improvements,and Lease Intangibles	162,922
Personal Property	99
Total real estate properties	167,221
Accumulated Depreciation	$ (60,389)
Medical office/outpatient [Member] | Colorado [Member]
Summary of Company's investment
Number of facilities | property	9
Land	$ 16,514
Buildings, Improvements,and Lease Intangibles	131,760
Personal Property	273
Total real estate properties	148,547
Accumulated Depreciation	$ (20,315)
Medical office/outpatient [Member] | Virginia [Member]
Summary of Company's investment
Number of facilities | property	7
Land	$ 0
Buildings, Improvements,and Lease Intangibles	147,809
Personal Property	106
Total real estate properties	147,915
Accumulated Depreciation	$ (38,288)
Medical office/outpatient [Member] | Hawaii [Member]
Summary of Company's investment
Number of facilities | property	3
Land	$ 8,327
Buildings, Improvements,and Lease Intangibles	134,037
Personal Property	159
Total real estate properties	142,523
Accumulated Depreciation	$ (34,703)
Medical office/outpatient [Member] | Iowa [Member]
Summary of Company's investment
Number of facilities | property	7
Land	$ 12,665
Buildings, Improvements,and Lease Intangibles	127,063
Personal Property	99
Total real estate properties	139,827
Accumulated Depreciation	$ (30,376)
Medical office/outpatient [Member] | Houston, Texas [Member]
Summary of Company's investment
Number of facilities | property	8
Land	$ 13,672
Buildings, Improvements,and Lease Intangibles	118,918
Personal Property	77
Total real estate properties	132,667
Accumulated Depreciation	$ (39,195)
Medical office/outpatient [Member] | Oklahoma [Member]
Summary of Company's investment
Number of facilities | property	3
Land	$ 9,427
Buildings, Improvements,and Lease Intangibles	111,452
Personal Property	10
Total real estate properties	120,889
Accumulated Depreciation	$ (14,751)
Medical office/outpatient [Member] | San Francisco, California [Member]
Summary of Company's investment
Number of facilities | property	3
Land	$ 14,054
Buildings, Improvements,and Lease Intangibles	105,611
Personal Property	43
Total real estate properties	119,708
Accumulated Depreciation	$ (15,539)
Medical office/outpatient [Member] | Missouri [Member]
Summary of Company's investment
Number of facilities | property	1
Land	$ 1,989
Buildings, Improvements,and Lease Intangibles	109,304
Personal Property	0
Total real estate properties	111,293
Accumulated Depreciation	$ (14,893)
Medical office/outpatient [Member] | Austin, Texas [Member]
Summary of Company's investment
Number of facilities | property	5
Land	$ 14,236
Buildings, Improvements,and Lease Intangibles	91,816
Personal Property	119
Total real estate properties	106,171
Accumulated Depreciation	$ (20,766)
Medical office/outpatient [Member] | Washington, D.C. [Member]
Summary of Company's investment
Number of facilities | property	4
Land	$ 0
Buildings, Improvements,and Lease Intangibles	101,186
Personal Property	8
Total real estate properties	101,194
Accumulated Depreciation	$ (20,701)
Medical office/outpatient [Member] | Memphis, Tennessee [Member]
Summary of Company's investment
Number of facilities | property	7
Land	$ 5,241
Buildings, Improvements,and Lease Intangibles	90,966
Personal Property	191
Total real estate properties	96,398
Accumulated Depreciation	$ (35,109)
Medical office/outpatient [Member] | San Antonio, Texas [Member]
Summary of Company's investment
Number of facilities | property	7
Land	$ 6,647
Buildings, Improvements,and Lease Intangibles	88,954
Personal Property	378
Total real estate properties	95,979
Accumulated Depreciation	$ (37,877)
Medical office/outpatient [Member] | Illinois [Member]
Summary of Company's investment
Number of facilities | property	3
Land	$ 5,859
Buildings, Improvements,and Lease Intangibles	86,068
Personal Property	201
Total real estate properties	92,128
Accumulated Depreciation	$ (19,372)
Medical office/outpatient [Member] | Indiana [Member]
Summary of Company's investment
Number of facilities | property	3
Land	$ 3,299
Buildings, Improvements,and Lease Intangibles	72,360
Personal Property	0
Total real estate properties	75,659
Accumulated Depreciation	$ (21,299)
Medical office/outpatient [Member] | Minnesota [Member]
Summary of Company's investment
Number of facilities | property	4
Land	$ 2,090
Buildings, Improvements,and Lease Intangibles	61,761
Personal Property	0
Total real estate properties	63,851
Accumulated Depreciation	$ (7,750)
Medical office/outpatient [Member] | Other (20 markets) [Member]
Summary of Company's investment
Number of facilities | property	39
Land	$ 17,431
Buildings, Improvements,and Lease Intangibles	507,551
Personal Property	1,190
Total real estate properties	526,172
Accumulated Depreciation	$ (190,586)