Goodwill - Changes in Goodwill by Reportable Segments (Detail) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Goodwill [Roll Forward]
Beginning balance	$ 6,919,109	$ 6,787,635
Acquisitions	28,323	130,057
Divestitures		(8,293)
Foreign currency and other adjustments	(3,767)	9,710
Ending balance	6,943,665	6,919,109
Goodwill, before accumulated impairment charges	7,075,816
Accumulated impairment charges	(132,151)
Ending balance	6,943,665	6,919,109
U.S. dialysis
Goodwill [Roll Forward]
Beginning balance	6,309,928	6,287,100
Acquisitions	3,481	24,377
Divestitures		(1,549)
Foreign currency and other adjustments	0	0
Ending balance	6,313,409	6,309,928
Goodwill, before accumulated impairment charges	6,313,409
Accumulated impairment charges	0
Ending balance	6,313,409	6,309,928
Other—Ancillary services
Goodwill [Roll Forward]
Beginning balance	609,181	500,535
Acquisitions	24,842	105,680
Divestitures		(6,744)
Foreign currency and other adjustments	(3,767)	9,710
Ending balance	630,256	609,181
Goodwill, before accumulated impairment charges	762,407
Accumulated impairment charges	(132,151)
Ending balance	$ 630,256	$ 609,181