Segment Reporting - Summary of Segment Net Revenues, Segment Operating Income (Loss) and Reconciliation of Segment Income to Consolidated Income from Continuing Operations Before Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Dialysis and related lab patient service revenues									$ 10,709,981	$ 10,093,670	$ 9,727,360
Provision for uncollectible accounts									(49,587)	(485,364)	(431,304)
Net dialysis and related lab patient service revenues									10,660,394	9,608,306	9,296,056
Other revenues									744,457	1,268,328	1,411,411
Total revenues	$ 2,821,124	$ 2,847,330	$ 2,886,953	$ 2,849,444	$ 2,780,913	$ 2,765,071	$ 2,699,399	$ 2,631,251	11,404,851	10,876,634	10,707,467
Operating income	$ 387,908	$ 289,038	$ 438,192	$ 410,686	$ 150,337	$ 395,294	$ 391,196	$ 875,928	1,525,824	1,812,755	2,029,710
Corporate administrative support									(90,108)	(44,966)	(13,628)
Debt expense									(487,435)	(430,634)	(414,116)
Other income									10,089	17,665	7,511
Income from continuing operations before income taxes									1,048,478	1,399,786	1,623,105
U.S. dialysis and related lab services
Segment Reporting Information [Line Items]
Total revenues									10,242,999	9,304,889	9,110,834
Other ancillary services and strategic initiatives
Segment Reporting Information [Line Items]
Total revenues									1,161,852	1,571,745	1,596,633
Operating Segments
Segment Reporting Information [Line Items]
Total revenues									11,532,037	10,956,413	10,759,561
Operating income									1,615,932	1,857,721	2,043,338
Operating Segments | U.S. dialysis and related lab services
Segment Reporting Information [Line Items]
Dialysis and related lab patient service revenues									10,366,996	9,822,299	9,551,422
Provision for uncollectible accounts									(50,927)	481,973	(429,878)
Net dialysis and related lab patient service revenues									10,316,069	9,340,326	9,121,544
Other revenues									19,880	19,739	16,645
Total revenues									10,335,949	9,360,065	9,138,189
Operating income									1,709,721	2,297,198	1,777,014
Operating Segments | U.S. dialysis and related lab services | External Sources
Segment Reporting Information [Line Items]
Dialysis and related lab patient service revenues									10,274,046	9,767,123	9,524,067
Operating Segments | U.S. dialysis and related lab services | Intersubsegment Eliminations
Segment Reporting Information [Line Items]
Dialysis and related lab patient service revenues									92,950	55,176	27,355
Operating Segments | Other ancillary services and strategic initiatives
Segment Reporting Information [Line Items]
Dialysis and related lab patient service revenues									437,275	323,156	201,867
Other revenues									724,577	1,248,589	1,394,766
Total revenues									1,196,088	1,596,348	1,621,372
Operating income									(93,789)	(439,477)	266,324
Operating Segments | Other ancillary services and strategic initiatives | Intersubsegment Eliminations
Segment Reporting Information [Line Items]
Dialysis and related lab patient service revenues									34,236	24,603	24,739
Intersegment Elimination
Segment Reporting Information [Line Items]
Total revenues									(127,186)	(79,779)	(52,094)
Intersegment Elimination | U.S. dialysis and related lab services
Segment Reporting Information [Line Items]
Total revenues									(92,950)	(55,176)	(27,355)
Intersegment Elimination | Other ancillary services and strategic initiatives
Segment Reporting Information [Line Items]
Total revenues									$ (34,236)	$ (24,603)	$ (24,739)