Revenue Recognition Segment Revenue by Payor (Details) - USD ($)	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Disaggregation of Revenue [Line Items]
Dialysis and related lab patient service revenues	$ 2,718,403,000	$ 2,494,609,000	$ 5,309,477,000	$ 4,917,395,000
Other revenues	217,956,000	314,390,000	450,781,000	629,913,000
Total revenues	2,886,953,000	2,699,399,000	5,736,397,000	5,330,650,000
Intersegment Elimination
Disaggregation of Revenue [Line Items]
Other revenues	(29,285,000)	(19,409,000)	(57,906,000)	(37,577,000)
Total revenues	(29,285,000)	(19,409,000)	(57,906,000)	(37,577,000)
Medicare and Medicare Advantage
Disaggregation of Revenue [Line Items]
Dialysis and related lab patient service revenues	1,526,066,000	1,313,504,000	3,011,258,000	2,586,100,000
Other revenues	154,028,000	225,511,000	296,786,000	450,713,000
Medicaid and Managed Medicaid
Disaggregation of Revenue [Line Items]
Dialysis and related lab patient service revenues	150,288,000	151,286,000	307,783,000	295,871,000
Other revenues	16,158,000	19,020,000	31,949,000	37,615,000
Other Government Payors
Disaggregation of Revenue [Line Items]
Dialysis and related lab patient service revenues	196,868,000	153,316,000	386,526,000	293,070,000
Commercial Payors
Disaggregation of Revenue [Line Items]
Dialysis and related lab patient service revenues	815,871,000	780,188,000	1,618,568,000	1,550,780,000
Other revenues	17,006,000	26,812,000	57,427,000	52,020,000
Other
Disaggregation of Revenue [Line Items]
Other revenues	39,953,000	49,171,000	84,006,000	102,058,000
U.S. dialysis and related lab services
Disaggregation of Revenue [Line Items]
Total revenues	2,568,247,000	2,311,930,000	5,087,724,000	4,571,324,000
U.S. dialysis and related lab services \| Intersegment Elimination
Disaggregation of Revenue [Line Items]
Other revenues	(20,096,000)	(13,285,000)	(38,519,000)	(25,084,000)
U.S. dialysis and related lab services \| Medicare and Medicare Advantage
Disaggregation of Revenue [Line Items]
Dialysis and related lab patient service revenues	1,526,066,000	1,313,504,000	3,011,258,000	2,586,100,000
U.S. dialysis and related lab services \| Medicaid and Managed Medicaid
Disaggregation of Revenue [Line Items]
Dialysis and related lab patient service revenues	150,288,000	151,286,000	307,783,000	295,871,000
U.S. dialysis and related lab services \| Other Government Payors
Disaggregation of Revenue [Line Items]
Dialysis and related lab patient service revenues	110,338,000	90,712,000	217,458,000	182,704,000
U.S. dialysis and related lab services \| Commercial Payors
Disaggregation of Revenue [Line Items]
Dialysis and related lab patient service revenues	796,732,000	764,864,000	1,579,711,000	1,521,574,000
U.S. dialysis and related lab services \| Other
Disaggregation of Revenue [Line Items]
Other revenues	4,919,000	4,849,000	10,033,000	10,159,000
Other—Ancillary services and strategic initiatives
Disaggregation of Revenue [Line Items]
Total revenues	318,706,000	387,469,000	648,673,000	759,326,000
Other—Ancillary services and strategic initiatives \| Intersegment Elimination
Disaggregation of Revenue [Line Items]
Other revenues	(9,189,000)	(6,124,000)	(19,387,000)	(12,493,000)
Other—Ancillary services and strategic initiatives \| Medicare and Medicare Advantage
Disaggregation of Revenue [Line Items]
Other revenues	154,028,000	225,511,000	296,786,000	450,713,000
Other—Ancillary services and strategic initiatives \| Medicaid and Managed Medicaid
Disaggregation of Revenue [Line Items]
Other revenues	16,158,000	19,020,000	31,949,000	37,615,000
Other—Ancillary services and strategic initiatives \| Other Government Payors
Disaggregation of Revenue [Line Items]
Dialysis and related lab patient service revenues	86,530,000	62,604,000	169,068,000	110,366,000
Other—Ancillary services and strategic initiatives \| Commercial Payors
Disaggregation of Revenue [Line Items]
Dialysis and related lab patient service revenues	19,139,000	15,324,000	38,857,000	29,206,000
Other revenues	17,006,000	26,812,000	57,427,000	52,020,000
Other—Ancillary services and strategic initiatives \| Other
Disaggregation of Revenue [Line Items]
Other revenues	$ 35,034,000	$ 44,322,000	$ 73,973,000	$ 91,899,000