Segment Reporting - Summary of Expenditures for Property and Equipment by Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Expenditures for property and equipment	$ 987,138	$ 905,250	$ 829,095
U.S. dialysis and related lab services
Segment Reporting Information [Line Items]
Expenditures for property and equipment	856,108	769,732	675,994
Other ancillary services and strategic initiatives
Segment Reporting Information [Line Items]
Expenditures for property and equipment	45,806	40,377	68,702
DMG - Held for sale
Segment Reporting Information [Line Items]
Expenditures for property and equipment	$ 85,224	$ 95,141	$ 84,399