New Construction, Acquisitions, Dispositions and Property Exchange Transaction - Additional Information (Detail)	1 Months Ended				2 Months Ended	3 Months Ended					12 Months Ended
	Apr. 30, 2017 ft² Time	Mar. 31, 2017 USD ($)	May 31, 2015 USD ($) ft² Property	Feb. 28, 2015 USD ($) ft² Time Building	Feb. 28, 2015 USD ($) ft² Property Time	Dec. 31, 2016 USD ($) ft² Option	Sep. 30, 2016 USD ($) ft²	Jun. 30, 2016 USD ($) ft²	Mar. 31, 2016 USD ($) ft²	Mar. 31, 2015 ft² Property	Dec. 31, 2017 USD ($) Time	Dec. 31, 2016 USD ($) ft² Property Option	Dec. 31, 2015 USD ($)	Mar. 12, 2017
Business Acquisitions And Dispositions [Line Items]
Total purchase price											$ 9,000,000
Acquired intangible assets include in-place leases amortization period											7 years 7 months 6 days
Repayment of loan											$ 21,400,000
Total cash paid												$ 60,400,000
Non-recourse third-party debt						$ 7,100,000						7,100,000
Lessor Leasing Arrangements, Operating Leases, Renewal Term											5 years
Deposits on real estate assets													$ 150,000
Net intangible assets											$ 20,600,000
Intangible assets, accumulated amortization						$ 27,100,000					28,700,000	27,100,000
Cash received from divestitures											$ 65,220,000	$ 0	0
Cash received for property exchange transaction													2,000,000
Gain on property exchange													8,742,000
Piedmont Roswell Physician Center Sandy Springs GA
Business Acquisitions And Dispositions [Line Items]
Acquired intangible assets include in-place leases amortization period				15 years							12 years 4 months 24 days
Piedmont Vinings Physician Center Vinings GA
Business Acquisitions And Dispositions [Line Items]
Acquired intangible assets include in-place leases amortization period				15 years							12 years 4 months 24 days
Minimum
Business Acquisitions And Dispositions [Line Items]
Acquired intangible assets include in-place leases amortization period											6 years
Lease agreement period											3 years
Maximum
Business Acquisitions And Dispositions [Line Items]
Number of term renewal options | Option						5						5
Acquired intangible assets include in-place leases amortization period											12 years
Lease agreement period											15 years
In Place Leases
Business Acquisitions And Dispositions [Line Items]
Renewal Term (years)											4 years 4 months 24 days
Acquired intangible assets include in-place leases amortization period											4 years 4 months 24 days
Universal Health Services, Inc
Business Acquisitions And Dispositions [Line Items]
Number of term renewal options | Time											6
Additional renewal terms											5 years
Henderson Medical Plaza | Universal Health Services, Inc
Business Acquisitions And Dispositions [Line Items]
Number of term renewal options | Time	2
Additional renewal terms	10 years
Net rentable area | ft²	78,800
Ground lease agreement period	75 years
Amount invested in MOB under construction											$ 12,400,000
Sheffield Medical Building
Business Acquisitions And Dispositions [Line Items]
Number of assets acquired | Property			2
Net rentable area | ft²			36,700
Area of disposed building | ft²			73,446
Cash received for property exchange transaction			$ 2,000,000
Percentage of rentable area covered by the agreement			100.00%
Lease agreement period			15 years
Percentage of annual rent increase			3.00%
Gain on property exchange													8,700,000
St. Mary's Professional Office Building
Business Acquisitions And Dispositions [Line Items]
Net cash proceeds received from divestiture											57,300,000
Gain on divestiture of property											27,200,000
Arlington Medical Properties
Business Acquisitions And Dispositions [Line Items]
Total purchase price		$ 7,900,000
Ownership prior to minority interest purchase		85.00%
Remaining percentage owned by third party member														15.00%
Las Palmas Del Sol Emergency Center in El Paso
Business Acquisitions And Dispositions [Line Items]
Total purchase price											4,200,000
Transaction costs											$ 60,000
Percentage of building area leased											100.00%
Triple net lease agreement period											10 years
Renewal Term (years)											9 years
Number of term renewal options | Time											2
Additional renewal terms											5 years
The Health Center at Hamburg
Business Acquisitions And Dispositions [Line Items]
Total purchase price											$ 4,800,000
Transaction costs											$ 96,000
Percentage of building area leased											100.00%
Triple net lease agreement period											15 years
Renewal Term (years)											8 years 6 months
Number of term renewal options | Time											2
Additional renewal terms											5 years
2017 Acquisitions
Business Acquisitions And Dispositions [Line Items]
Acquired intangible assets include in-place leases amortization period											8 years 4 months 24 days
2704 North Tenaya Way and Frederick Memorial Hospital Crestwood
Business Acquisitions And Dispositions [Line Items]
Number of assets acquired | Property												2
2704 North Tenaya Way
Business Acquisitions And Dispositions [Line Items]
Total purchase price						$ 15,300,000
Net rentable area | ft²						45,000						45,000
Non-recourse third-party debt						$ 7,100,000						$ 7,100,000
2704 North Tenaya Way | Lease Agreements
Business Acquisitions And Dispositions [Line Items]
Renewal Term (years)						7 years 1 month 6 days
Frederick Memorial Hospital Crestwood
Business Acquisitions And Dispositions [Line Items]
Total purchase price							$ 24,300,000
Net rentable area | ft²							62,300
Frederick Memorial Hospital Crestwood | Lease Agreements
Business Acquisitions And Dispositions [Line Items]
Renewal Term (years)							12 years
Chandler Corporate Center III
Business Acquisitions And Dispositions [Line Items]
Total purchase price								$ 18,000,000
Net rentable area | ft²								82,000
Occupied percentage of property								92.00%
Lease rent escalation period								12 years
Lessor Leasing Arrangements, Operating Leases, Renewal Term								10 years
Chandler Corporate Center III | Lease Agreements
Business Acquisitions And Dispositions [Line Items]
Renewal Term (years)								11 years 3 months 18 days
Madison Professional Office Building
Business Acquisitions And Dispositions [Line Items]
Total purchase price									$ 10,100,000
Net rentable area | ft²									30,100
Deposits on real estate assets													$ 150,000
Madison Professional Office Building | Lease Agreements
Business Acquisitions And Dispositions [Line Items]
Renewal Term (years)									6 years 2 months 12 days
Haas Medical Office Park
Business Acquisitions And Dispositions [Line Items]
Total purchase price				$ 4,100,000
Acquired intangible assets include in-place leases amortization period				10 years 4 months 24 days							7 years 7 months 6 days
Net rentable area | ft²				16,000	16,000
Number of Buildings purchased | Building				2
Wholly Owned Subsidiaries Of U H S Real Property Of Two Newly Constructed And Recently Opened F E Ds Located In Weslaco And Mission Texas
Business Acquisitions And Dispositions [Line Items]
Total purchase price					$ 12,800,000
Number of term renewal options | Time				6	6
Additional renewal terms					5 years					5 years
Number of real properties purchased | Property					2					2
Lease agreement period					10 years					10 years
Wholly Owned Subsidiaries Of U H S Real Property Of Two Newly Constructed And Recently Opened F E Ds Located In Weslaco And Mission Texas | Recently Opened Free Standing Emergency Departments | Weslaco
Business Acquisitions And Dispositions [Line Items]
Area of acquired building | ft²				13,600	13,600					13,600
Wholly Owned Subsidiaries Of U H S Real Property Of Two Newly Constructed And Recently Opened F E Ds Located In Weslaco And Mission Texas | Recently Opened Free Standing Emergency Departments | Mission
Business Acquisitions And Dispositions [Line Items]
Area of acquired building | ft²				13,600	13,600					13,600