Basis of Presentation and Summary of Significant Accounting Policies - Disaggregation of Revenue by Each Payor Type (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Revenue	$ 180,123	$ 156,060	$ 510,397	$ 381,867
Commercial
Disaggregation of Revenue [Line Items]
Revenue	25,041	25,429	75,233	75,883
Medicare
Disaggregation of Revenue [Line Items]
Revenue	79,649	60,737	206,567	155,730
Medicaid
Disaggregation of Revenue [Line Items]
Revenue	65,849	61,189	200,746	122,837
Other third parties
Disaggregation of Revenue [Line Items]
Revenue	$ 9,584	$ 8,705	$ 27,851	$ 27,417