Accounts Receivable and Net Revenue - Schedule of Net Patient Service Revenue by Type of Payor (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Health Care Organization, Receivable and Revenue Disclosures [Line Items]
Percentage of net patient service revenue	100.00%	100.00%	100.00%	100.00%
Contracted Managed Care [Member]
Health Care Organization, Receivable and Revenue Disclosures [Line Items]
Percentage of net patient service revenue	69.00%	68.00%	69.00%	68.00%
Government [Member]
Health Care Organization, Receivable and Revenue Disclosures [Line Items]
Percentage of net patient service revenue	26.00%	26.00%	26.00%	26.00%
Other Third-Parties [Member]
Health Care Organization, Receivable and Revenue Disclosures [Line Items]
Percentage of net patient service revenue	4.00%	5.00%	4.00%	5.00%
Private-Pay Patients [Member]
Health Care Organization, Receivable and Revenue Disclosures [Line Items]
Percentage of net patient service revenue	1.00%	1.00%	1.00%	1.00%