Goodwill - Changes in Goodwill by Reportable Segments (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Goodwill [Roll Forward]
Beginning balance	$ 7,046,241	$ 6,919,109
Acquisitions	4,442	173,244
Divestitures	0	(1,745)
Foreign currency and other adjustments	22,220	(44,367)
Ending balance	7,072,903	7,046,241
Goodwill, before accumulated impairment charges	7,196,846
Accumulated impairment charges	(123,943)
Ending balance	7,072,903	7,046,241
U.S. dialysis
Goodwill [Roll Forward]
Beginning balance	6,400,162	6,309,928
Acquisitions	0	91,979
Divestitures	0	(1,745)
Foreign currency and other adjustments	0	0
Ending balance	6,400,162	6,400,162
Goodwill, before accumulated impairment charges	6,400,162
Accumulated impairment charges	0
Ending balance	6,400,162	6,400,162
Other—Ancillary services
Goodwill [Roll Forward]
Beginning balance	646,079	609,181
Acquisitions	4,442	81,265
Divestitures	0	0
Foreign currency and other adjustments	22,220	(44,367)
Ending balance	672,741	646,079
Goodwill, before accumulated impairment charges	796,684
Accumulated impairment charges	(123,943)
Ending balance	$ 672,741	$ 646,079