Segment Information - Summary of Financial Information by Operating Segment, Goodwill (Detail) $ in Thousands	3 Months Ended
Mar. 31, 2019 USD ($)
Goodwill:
Beginning balance	$ 2,396,412
Increase from 2019 acquisitions	34,523
Increase from contribution of redeemable noncontrolling interests	3,085
Foreign currency translation gain	7,979
Ending balance	2,441,999
U.S. Facilities [Member] \| Operating Segment [Member]
Goodwill:
Beginning balance	2,044,837
Increase from 2019 acquisitions	34,523
Increase from contribution of redeemable noncontrolling interests	3,085
Ending balance	2,082,445
U.K. Facilities [Member] \| Operating Segment [Member]
Goodwill:
Beginning balance	351,575
Foreign currency translation gain	7,979
Ending balance	$ 359,554

Goodwill, increase from contribution of redeemable noncontrolling interests.

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- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=77989000&loc=SL49117168-202975

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- Definition

Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
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-Section 50
-Paragraph 1
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- Definition

Amount of foreign currency translation gain (loss) which increases (decreases) an asset representing future economic benefits from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

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-Topic 350
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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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