Revenue Recognition and Accounts Receivable - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accounts receivable, net	$ 1,795,598,000	$ 1,858,608,000
Medicare bad debt claims
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accounts receivable, net	$ 1,038,248,000	$ 1,080,561,000
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
Concentration risk percentage	10.00%
Accounts receivable, net	$ 0
Percentage Of Accounts Receivable Six Months Or More Past Due	18.00%
Accounts Receivable Period Outstanding	6 months	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	$ 37,274,000	$ 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	$ 8,328,000	$ 52,924,000