Property Investments (Details) $ in Thousands	Dec. 31, 2016 USD ($) property	Dec. 31, 2015 USD ($) property
Summary of Company's investment
Number of facilities | property	202
Number of real estate investments | property	202
Land	$ 219,795
Buildings, Improvements,and Lease Intangibles	3,386,480	$ 3,135,893
Buildings, Improvements, and Lease Intangibles, including Construction in Progress	3,398,135
Personal Property	10,291	9,954
Total real estate properties	3,628,221	3,380,908
Accumulated Depreciation	(840,839)	$ (761,926)
Total real estate investments	3,628,221
Wholly Owned Properties [Member]
Summary of Company's investment
Accumulated Depreciation	$ (840,839)
Land Held for Development and Corporate Property [Member]
Summary of Company's investment
Number of facilities | property	0
Land	$ 20,123
Buildings, Improvements,and Lease Intangibles	11,655
Personal Property	5,583
Total real estate properties	37,361
Accumulated Depreciation	$ (4,333)
Land Held for Development [Member]
Summary of Company's investment
Number of facilities | property	0
Land	$ 20,123
Buildings, Improvements,and Lease Intangibles	0
Personal Property	0
Total real estate properties	20,123
Accumulated Depreciation	(166)
Construction in Progress [Member]
Summary of Company's investment
Buildings, Improvements,and Lease Intangibles	11,655
Total real estate properties	$ 11,655
Corporate Property [Member]
Summary of Company's investment
Number of facilities | property	0
Land	$ 0
Buildings, Improvements,and Lease Intangibles	0
Personal Property	5,583
Total real estate properties	5,583
Accumulated Depreciation	$ (4,167)
Tennessee [Member]
Summary of Company's investment
Number of facilities | property		2
Medical office/outpatient [Member]
Summary of Company's investment
Number of facilities | property	182
Land	$ 183,266
Buildings, Improvements,and Lease Intangibles	2,978,792
Personal Property	3,810
Total real estate properties	3,165,868
Accumulated Depreciation	$ (735,052)
Medical office/outpatient [Member] | Alabama [Member]
Summary of Company's investment
Number of facilities | property	4
Land	$ 650
Buildings, Improvements,and Lease Intangibles	43,912
Personal Property	20
Total real estate properties	44,582
Accumulated Depreciation	$ (19,771)
Medical office/outpatient [Member] | Arizona [Member]
Summary of Company's investment
Number of facilities | property	7
Land	$ 1,330
Buildings, Improvements,and Lease Intangibles	62,289
Personal Property	443
Total real estate properties	64,062
Accumulated Depreciation	$ (16,082)
Medical office/outpatient [Member] | California [Member]
Summary of Company's investment
Number of facilities | property	12
Land	$ 37,072
Buildings, Improvements,and Lease Intangibles	201,860
Personal Property	325
Total real estate properties	239,257
Accumulated Depreciation	$ (71,152)
Medical office/outpatient [Member] | Colorado [Member]
Summary of Company's investment
Number of facilities | property	10
Land	$ 8,257
Buildings, Improvements,and Lease Intangibles	198,119
Personal Property	239
Total real estate properties	206,615
Accumulated Depreciation	$ (31,357)
Medical office/outpatient [Member] | DISTRICT OF COLUMBIA
Summary of Company's investment
Number of facilities | property	2
Land	$ 0
Buildings, Improvements,and Lease Intangibles	31,564
Personal Property	0
Total real estate properties	31,564
Accumulated Depreciation	$ (11,293)
Medical office/outpatient [Member] | Florida [Member]
Summary of Company's investment
Number of facilities | property	7
Land	$ 6,873
Buildings, Improvements,and Lease Intangibles	71,558
Personal Property	112
Total real estate properties	78,543
Accumulated Depreciation	$ (37,988)
Medical office/outpatient [Member] | Hawaii [Member]
Summary of Company's investment
Number of facilities | property	3
Land	$ 8,327
Buildings, Improvements,and Lease Intangibles	131,207
Personal Property	160
Total real estate properties	139,694
Accumulated Depreciation	$ (25,869)
Medical office/outpatient [Member] | Illinois [Member]
Summary of Company's investment
Number of facilities | property	3
Land	$ 6,142
Buildings, Improvements,and Lease Intangibles	51,620
Personal Property	151
Total real estate properties	57,913
Accumulated Depreciation	$ (14,669)
Medical office/outpatient [Member] | Indiana [Member]
Summary of Company's investment
Number of facilities | property	4
Land	$ 3,299
Buildings, Improvements,and Lease Intangibles	118,219
Personal Property	40
Total real estate properties	121,558
Accumulated Depreciation	$ (24,216)
Medical office/outpatient [Member] | Iowa [Member]
Summary of Company's investment
Number of facilities | property	6
Land	$ 12,665
Buildings, Improvements,and Lease Intangibles	80,742
Personal Property	94
Total real estate properties	93,501
Accumulated Depreciation	$ (17,784)
Medical office/outpatient [Member] | Minnesota [Member]
Summary of Company's investment
Number of facilities | property	3
Land	$ 2,090
Buildings, Improvements,and Lease Intangibles	46,243
Personal Property	0
Total real estate properties	48,333
Accumulated Depreciation	$ (2,528)
Medical office/outpatient [Member] | Missouri [Member]
Summary of Company's investment
Number of facilities | property	3
Land	$ 3,797
Buildings, Improvements,and Lease Intangibles	28,796
Personal Property	7
Total real estate properties	32,600
Accumulated Depreciation	$ (16,810)
Medical office/outpatient [Member] | North Carolina [Member]
Summary of Company's investment
Number of facilities | property	16
Land	$ 5,096
Buildings, Improvements,and Lease Intangibles	158,488
Personal Property	95
Total real estate properties	163,679
Accumulated Depreciation	$ (49,158)
Medical office/outpatient [Member] | Oklahoma [Member]
Summary of Company's investment
Number of facilities | property	2
Land	$ 7,673
Buildings, Improvements,and Lease Intangibles	101,416
Personal Property	0
Total real estate properties	109,089
Accumulated Depreciation	$ (7,747)
Medical office/outpatient [Member] | Tennessee [Member]
Summary of Company's investment
Number of facilities | property	13
Land	$ 11,750
Buildings, Improvements,and Lease Intangibles	223,425
Personal Property	303
Total real estate properties	235,478
Accumulated Depreciation	$ (67,614)
Medical office/outpatient [Member] | Texas [Member]
Summary of Company's investment
Number of facilities | property	43
Land	$ 45,117
Buildings, Improvements,and Lease Intangibles	643,386
Personal Property	1,262
Total real estate properties	689,765
Accumulated Depreciation	$ (190,829)
Medical office/outpatient [Member] | Virginia [Member]
Summary of Company's investment
Number of facilities | property	14
Land	$ 3,334
Buildings, Improvements,and Lease Intangibles	227,296
Personal Property	139
Total real estate properties	230,769
Accumulated Depreciation	$ (47,309)
Medical office/outpatient [Member] | Washington [Member]
Summary of Company's investment
Number of facilities | property	17
Land	$ 17,437
Buildings, Improvements,and Lease Intangibles	406,980
Personal Property	314
Total real estate properties	424,731
Accumulated Depreciation	$ (42,848)
Medical office/outpatient [Member] | Other (11 states) [Member]
Summary of Company's investment
Number of facilities | property	13
Land	$ 2,357
Buildings, Improvements,and Lease Intangibles	151,672
Personal Property	106
Total real estate properties	154,135
Accumulated Depreciation	$ (40,028)
Inpatient [Member]
Summary of Company's investment
Number of facilities | property	10
Land	$ 13,245
Buildings, Improvements,and Lease Intangibles	330,541
Personal Property	265
Total real estate properties	344,051
Accumulated Depreciation	$ (75,518)
Inpatient [Member] | California [Member]
Summary of Company's investment
Number of facilities | property	1
Land	$ 0
Buildings, Improvements,and Lease Intangibles	12,688
Personal Property	0
Total real estate properties	12,688
Accumulated Depreciation	$ (7,281)
Inpatient [Member] | Colorado [Member]
Summary of Company's investment
Number of facilities | property	1
Land	$ 623
Buildings, Improvements,and Lease Intangibles	10,788
Personal Property	0
Total real estate properties	11,411
Accumulated Depreciation	$ (1,308)
Inpatient [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	$ (9,198)
Inpatient [Member] | Pennsylvania [Member]
Summary of Company's investment
Number of facilities | property	2
Land	$ 1,126
Buildings, Improvements,and Lease Intangibles	39,585
Personal Property	0
Total real estate properties	40,711
Accumulated Depreciation	$ (22,826)
Inpatient [Member] | Texas [Member]
Summary of Company's investment
Number of facilities | property	5
Land	$ 9,507
Buildings, Improvements,and Lease Intangibles	158,176
Personal Property	265
Total real estate properties	167,948
Accumulated Depreciation	$ (34,905)
Other [Member]
Summary of Company's investment
Number of facilities | property	10
Land	$ 3,161
Buildings, Improvements,and Lease Intangibles	77,147
Personal Property	633
Total real estate properties	80,941
Accumulated Depreciation	$ (25,936)
Other [Member] | Indiana [Member]
Summary of Company's investment
Number of facilities | property	1
Land	$ 96
Buildings, Improvements,and Lease Intangibles	3,662
Personal Property	32
Total real estate properties	3,790
Accumulated Depreciation	$ (2,708)
Other [Member] | Iowa [Member]
Summary of Company's investment
Number of facilities | property	1
Land	$ 0
Buildings, Improvements,and Lease Intangibles	40,339
Personal Property	5
Total real estate properties	40,344
Accumulated Depreciation	$ (5,642)
Other [Member] | Michigan [Member]
Summary of Company's investment
Number of facilities | property	5
Land	$ 193
Buildings, Improvements,and Lease Intangibles	12,728
Personal Property	183
Total real estate properties	13,104
Accumulated Depreciation	$ (9,173)
Other [Member] | Tennessee [Member]
Summary of Company's investment
Number of facilities | property	1
Land	$ 253
Buildings, Improvements,and Lease Intangibles	7,213
Personal Property	409
Total real estate properties	7,875
Accumulated Depreciation	$ (2,625)
Other [Member] | Texas [Member]
Summary of Company's investment
Number of facilities | property	1
Land	$ 1,480
Buildings, Improvements,and Lease Intangibles	3,872
Personal Property	2
Total real estate properties	5,354
Accumulated Depreciation	$ (64)
Other [Member] | Virginia [Member]
Summary of Company's investment
Number of facilities | property	1
Land	$ 1,139
Buildings, Improvements,and Lease Intangibles	9,333
Personal Property	2
Total real estate properties	10,474
Accumulated Depreciation	$ (5,724)