Revenue Recognition and Accounts Receivable Revenue Recognition Segment Revenue by Payor (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
Disaggregation of Revenue [Line Items]
Patient service revenues									$ 10,709,981	$ 10,093,670	$ 9,727,360
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
Intersegment Elimination
Disaggregation of Revenue [Line Items]
Total revenues									(127,186)	(79,779)	(52,094)
Medicare and Medicare Advantage
Disaggregation of Revenue [Line Items]
Patient service revenues									6,063,891	5,253,012	5,303,718
Other revenues									492,812	902,289	974,146
Medicaid and Managed Medicaid
Disaggregation of Revenue [Line Items]
Patient service revenues									628,766	606,827	319,553
Other revenues									44,246	71,426	82,428
Other Government Payors
Disaggregation of Revenue [Line Items]
Patient service revenues									782,593	622,218	308,400
Commercial Payors
Disaggregation of Revenue [Line Items]
Patient service revenues									3,278,094	3,181,425	3,391,740
Other revenues									90,890	116,503	128,824
Other
Disaggregation of Revenue [Line Items]
Other revenues									150,745	202,713	250,752
U.S. dialysis and related lab services
Disaggregation of Revenue [Line Items]
Total revenues									10,242,999	9,304,889	9,110,834
U.S. dialysis and related lab services | Intersegment Elimination
Disaggregation of Revenue [Line Items]
Total revenues									(92,950)	(55,176)	(27,355)
U.S. dialysis and related lab services | Medicare and Medicare Advantage
Disaggregation of Revenue [Line Items]
Patient service revenues									6,063,891	5,253,012	5,303,718
Other revenues									0	0	0
U.S. dialysis and related lab services | Medicaid and Managed Medicaid
Disaggregation of Revenue [Line Items]
Patient service revenues									628,766	606,827	319,553
Other revenues									0	0	0
U.S. dialysis and related lab services | Other Government Payors
Disaggregation of Revenue [Line Items]
Patient service revenues									446,999	362,567	143,207
U.S. dialysis and related lab services | Commercial Payors
Disaggregation of Revenue [Line Items]
Patient service revenues									3,176,413	3,117,920	3,355,066
Other revenues									0	0	0
U.S. dialysis and related lab services | Other
Disaggregation of Revenue [Line Items]
Other revenues									19,880	19,739	16,645
Other ancillary services and strategic initiatives
Disaggregation of Revenue [Line Items]
Total revenues									1,161,852	1,571,745	1,596,633
Other ancillary services and strategic initiatives | Intersegment Elimination
Disaggregation of Revenue [Line Items]
Total revenues									(34,236)	(24,603)	(24,739)
Other ancillary services and strategic initiatives | Medicare and Medicare Advantage
Disaggregation of Revenue [Line Items]
Patient service revenues									0	0	0
Other revenues									492,812	902,289	974,146
Other ancillary services and strategic initiatives | Medicaid and Managed Medicaid
Disaggregation of Revenue [Line Items]
Patient service revenues									0	0	0
Other revenues									44,246	71,426	82,428
Other ancillary services and strategic initiatives | Other Government Payors
Disaggregation of Revenue [Line Items]
Patient service revenues									335,594	259,651	165,193
Other ancillary services and strategic initiatives | Commercial Payors
Disaggregation of Revenue [Line Items]
Patient service revenues									101,681	63,505	36,674
Other revenues									90,890	116,503	128,824
Other ancillary services and strategic initiatives | Other
Disaggregation of Revenue [Line Items]
Other revenues									$ 130,865	$ 182,974	$ 234,107