Organization and Summary of Significant Accounting Policies - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 segment patient state country clinic entity	Jan. 01, 2019 USD ($)
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Operating divisions | segment	2
Number of legal entities that third parties held noncontrolling equity interests | entity	653
Minimum | Noncompetition and other agreements
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Amortization period	2 years
Minimum | Buildings
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Property, and equipment useful lives	20 years
Minimum | Leasehold Improvements
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Property, and equipment useful lives	10 years
Minimum | Equipment and Information Systems
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Property, and equipment useful lives	3 years
Maximum | Noncompetition and other agreements
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Amortization period	10 years
Maximum | Buildings
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Property, and equipment useful lives	40 years
Maximum | Equipment and Information Systems
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Property, and equipment useful lives	15 years
United States
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Number of dialysis centers that the company operated or provided administrative services | clinic	2,664
Number of states where dialysis centers are located | state	46
Number of patients served | patient	202,700
International Operations
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Number of dialysis centers that the company operated or provided administrative services | clinic	241
Number of patients served | patient	25,000
Number of countries in which dialysis centers located | country	9
Continuing Operations
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Number of legal entities that third parties held noncontrolling equity interests | entity	650
Adjustments for New Accounting Pronouncement [Member] | Scenario, Forecast
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Net lease liabilities | $		$ 3,000,000