Accounts Receivable and Net Revenue - Schedule of Net Revenue (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disaggregation of Revenue [Abstract]
Net revenue	$ 472,959	$ 415,441	$ 919,712	$ 856,686
Net patient service revenue [Member]
Disaggregation of Revenue [Abstract]
Net revenue	412,950	354,763	794,012	739,199
Hospital contract administrative fees [Member]
Disaggregation of Revenue [Abstract]
Net revenue	58,904	52,989	115,970	104,832
Other revenue [Member]
Disaggregation of Revenue [Abstract]
Net revenue	$ 1,105	$ 7,689	$ 9,730	$ 12,655