Summary of Segment Net Revenues, Segment Operating Income (Loss) and Reconciliation of Segment Income to Consolidated Income Before Income Taxes (Detail) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
Segment Reporting Information [Line Items]
Patient service revenues		$ 2,601,378	$ 2,481,933
Less: Provision for uncollectible accounts		(112,983)	(109,205)
Net dialysis and related lab services patient service revenues		2,488,395	2,372,728
Other revenues		290,852	321,361
Total net operating revenues		3,697,283	3,581,136
Capitated revenues		918,036	887,047
Operating income (loss)		888,236	364,889
Corporate administrative support		(10,592)	(6,921)
Debt expense		(104,429)	(102,884)
Other income, net		4,243	2,976
Consolidated income before income taxes		788,050	264,981
Operating Segments
Segment Reporting Information [Line Items]
Total net operating revenues		3,736,404	3,607,342
Operating income (loss)		898,828	371,810
Operating Segments | U.S. dialysis and related lab services
Segment Reporting Information [Line Items]
Patient service revenues		2,372,661	2,327,971
Less: Provision for uncollectible accounts		(106,770)	(104,751)
Net dialysis and related lab services patient service revenues		2,265,891	2,223,220
Other revenues	[1]	5,303	3,973
Total net operating revenues		2,271,194	2,227,193
Operating income (loss)	[2]	944,740	440,055
Operating Segments | U.S. dialysis and related lab services | External Sources
Segment Reporting Information [Line Items]
Patient service revenues		2,348,901	2,313,663
Operating Segments | U.S. dialysis and related lab services | Intersubsegment Eliminations
Segment Reporting Information [Line Items]
Patient service revenues		23,760	14,308
Operating Segments | DMG
Segment Reporting Information [Line Items]
Net dialysis and related lab services patient service revenues		178,971	112,433
Other revenues	[3]	18,269	10,335
Total net operating revenues		1,086,985	988,858
Capitated revenues		889,686	866,019
Operating income (loss)		12,308	(57,145)
Operating Segments | DMG | Intersubsegment Eliminations
Segment Reporting Information [Line Items]
Other revenues		59	71
Operating Segments | Ancillary services and strategic initiatives
Segment Reporting Information [Line Items]
Net dialysis and related lab services patient service revenues		67,293	51,383
Other revenues		267,280	307,053
Total net operating revenues		378,225	391,291
Capitated revenues		28,350	21,028
Operating income (loss)		(58,220)	(11,100)
Operating Segments | Ancillary services and strategic initiatives | Intersubsegment Eliminations
Segment Reporting Information [Line Items]
Total net operating revenues		15,302	11,827
Intersegment Elimination
Segment Reporting Information [Line Items]
Total net operating revenues		$ (39,121)	$ (26,206)

[1] (1)Includes management fees for providing management and administrative services to dialysis centers that are wholly-owned by third parties and legal entities in which the Company owns a noncontrolling equity investment.

[2] U.S. dialysis and related lab services operating income includes the net gain on the settlement with the VA.

[3] Includes medical consulting service fees and management fees for providing management and administrative services to unconsolidated joint ventures, as well as revenue related to the maintenance of existing physician networks.