Revenue Recognition and Receivables - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Total revenues	$ 563,462
Total revenues, as a percent	100.00%
Medicaid
Disaggregation of Revenue [Line Items]
Total revenues	$ 267,015
Total revenues, as a percent	47.40%
Medicare
Disaggregation of Revenue [Line Items]
Total revenues	$ 110,794
Total revenues, as a percent	19.70%
Managed Care
Disaggregation of Revenue [Line Items]
Total revenues	$ 53,242
Total revenues, as a percent	9.40%
Private Pay and other
Disaggregation of Revenue [Line Items]
Total revenues	$ 132,411
Total revenues, as a percent	23.50%
Calculated under Revenue Guidance in Effect before Topic 606
Disaggregation of Revenue [Line Items]
Total revenues	$ 577,657	$ 574,794
Total revenues, as a percent	100.00%	100.00%
Calculated under Revenue Guidance in Effect before Topic 606 | Medicaid
Disaggregation of Revenue [Line Items]
Total revenues	$ 303,412	$ 300,926
Total revenues, as a percent	52.50%	52.40%
Calculated under Revenue Guidance in Effect before Topic 606 | Medicare
Disaggregation of Revenue [Line Items]
Total revenues	$ 143,104	$ 149,020
Total revenues, as a percent	24.80%	25.90%
Calculated under Revenue Guidance in Effect before Topic 606 | Managed Care
Disaggregation of Revenue [Line Items]
Total revenues	$ 46,988	$ 42,673
Total revenues, as a percent	8.10%	7.40%
Calculated under Revenue Guidance in Effect before Topic 606 | Private Pay and other
Disaggregation of Revenue [Line Items]
Total revenues	$ 84,153	$ 82,175
Total revenues, as a percent	14.60%	14.30%