Segment Information - Summary of Financial Information by Operating Segment, Goodwill (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2016 USD ($)
Goodwill:
Beginning balance	$ 2,128,215
Increase from 2016 acquisitions	764,189
Foreign currency translation	(68,990)
Purchase price allocation and other	8,787
Ending balance	2,832,201
U.S. Facilities [Member]
Goodwill:
Beginning balance	1,941,873
Increase from 2016 acquisitions	95,274
Purchase price allocation and other	8,748
Ending balance	2,045,895
U.K. Facilities [Member]
Goodwill:
Beginning balance	186,342
Increase from 2016 acquisitions	668,915
Foreign currency translation	(68,990)
Purchase price allocation and other	39
Ending balance	$ 786,306