Basis of Presentation and Summary of Significant Accounting Policies - Disaggregation of Revenue by Each Payor Type (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Disaggregation of Revenue [Line Items]
Revenue	$ 165,169	$ 130,050	$ 330,274	$ 225,806
Commercial
Disaggregation of Revenue [Line Items]
Revenue	25,479	25,365	50,192	50,383
Medicare
Disaggregation of Revenue [Line Items]
Revenue	62,038	57,965	126,918	95,063
Medicaid
Disaggregation of Revenue [Line Items]
Revenue	68,450	36,277	134,897	61,647
Other third parties
Disaggregation of Revenue [Line Items]
Revenue	$ 9,202	$ 10,443	$ 18,267	$ 18,713