Accounts Receivable and Net Revenue - Schedule of Net Patient Service Revenue by Type of Payor (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
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	65.00%	69.00%	67.00%	69.00%
Government [Member]
Health Care Organization, Receivable and Revenue Disclosures [Line Items]
Percentage of net patient service revenue	28.00%	26.00%	26.00%	25.00%
Other Third-Parties [Member]
Health Care Organization, Receivable and Revenue Disclosures [Line Items]
Percentage of net patient service revenue	5.00%	3.00%	5.00%	4.00%
Private-Pay Patients [Member]
Health Care Organization, Receivable and Revenue Disclosures [Line Items]
Percentage of net patient service revenue	2.00%	2.00%	2.00%	2.00%