Goodwill - Changes in Goodwill by Reportable Segments (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2025	Dec. 31, 2024
Goodwill [Roll Forward]
Beginning balance	$ 7,375,216	$ 7,112,560
Acquisitions	398	349,069
Divestitures		(3,193)
Foreign currency and other adjustments	39,946	(83,220)
Ending balance	7,415,560	7,375,216
Goodwill, before accumulated impairment charges	7,562,172
Accumulated impairment charges	(146,612)
Ending balance	7,415,560	7,375,216
U S Dialysis And Related Lab Services [Member]
Goodwill [Roll Forward]
Beginning balance	6,517,220	6,416,825
Acquisitions	5,236	102,082
Divestitures		(1,687)
Foreign currency and other adjustments	0	0
Ending balance	6,522,456	6,517,220
Goodwill, before accumulated impairment charges	6,522,456
Accumulated impairment charges	0
Ending balance	6,522,456	6,517,220
Other Operating Segment [Member]
Goodwill [Roll Forward]
Beginning balance	857,996	695,735
Acquisitions	(4,838)	246,987
Divestitures		(1,506)
Foreign currency and other adjustments	39,946	(83,220)
Ending balance	893,104	857,996
Goodwill, before accumulated impairment charges	1,039,716
Accumulated impairment charges	(146,612)
Ending balance	$ 893,104	$ 857,996