Segment Information - Summary of Financial Information by Operating Segment, Goodwill (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($)
Goodwill:
Goodwill	$ 2,775,006
Accumulated impairment loss	(325,875)
Net goodwill, beginning balance	2,449,131
Prior period purchase price adjustments	(13)
Foreign currency translation gain	(22,418)
Goodwill	2,752,575
Accumulated impairment loss	(325,875)
Net goodwill, ending balance	2,426,700
U.S. Facilities [Member] | Operating Segment [Member]
Goodwill:
Goodwill	2,085,104
Net goodwill, beginning balance	2,085,104
Prior period purchase price adjustments	(13)
Goodwill	2,085,091
Net goodwill, ending balance	2,085,091
U.K. Facilities [Member] | Operating Segment [Member]
Goodwill:
Goodwill	689,902
Accumulated impairment loss	(325,875)
Net goodwill, beginning balance	364,027
Foreign currency translation gain	(22,418)
Goodwill	667,484
Accumulated impairment loss	(325,875)
Net goodwill, ending balance	$ 341,609