Revenue Recognition and Accounts Receivable - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Provision for uncollectible accounts	$ 49,587,000	$ 485,364,000	$ 431,304,000
Accounts receivable, net	1,858,608,000	1,714,750,000
Medicare bad debt claims
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accounts receivable, net	$ 1,080,561,000	$ 874,971,000
Accounts Receivable
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accounts Receivable Period Outstanding	1 year
Patient Services Customer Concentration Risk | Accounts Receivable
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Number Of Concentration Risk Customers	0	0
Percentage of U.S. dialysis service revenues related to government-based programs	10.00%	10.00%
Accounts receivable, net	$ 0
Percentage Of Accounts Receivable Six Months Or More Past Due	18.00%	21.00%
Accounts Receivable Period Outstanding	6 months
Difference between Revenue Guidance in Effect before and after Topic 606
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Contract with Customer, Performance Obligation Satisfied in Previous Period	$ 88,495,000
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	36,000,000
Accounts Receivable
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accounts receivable, allowance	$ 52,924,000	$ 218,399,000