Goodwill - Changes in Goodwill by Reportable Segments (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2023	Dec. 31, 2022
Goodwill [Roll Forward]
Beginning balance	$ 7,076,610	$ 7,046,241
Acquisitions	4,688	49,047
Divestitures		(3,350)
Foreign currency and other adjustments	6,925	(15,328)
Ending balance	7,088,223	7,076,610
Goodwill, before accumulated impairment charges	7,206,163
Accumulated impairment charges	(117,940)
Ending balance	7,088,223	7,076,610
U.S. dialysis
Goodwill [Roll Forward]
Beginning balance	6,416,825	6,400,162
Acquisitions	0	16,750
Divestitures		(87)
Foreign currency and other adjustments	0	0
Ending balance	6,416,825	6,416,825
Goodwill, before accumulated impairment charges	6,416,825
Accumulated impairment charges	0
Ending balance	6,416,825	6,416,825
Other—Ancillary services
Goodwill [Roll Forward]
Beginning balance	659,785	646,079
Acquisitions	4,688	32,297
Divestitures		(3,263)
Foreign currency and other adjustments	6,925	(15,328)
Ending balance	671,398	659,785
Goodwill, before accumulated impairment charges	789,338
Accumulated impairment charges	(117,940)
Ending balance	$ 671,398	$ 659,785