Accrued Expenses and Other Current Liabilities and Other Liabilities - Accrued expenses and other current liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Accrued Expenses and Other Current Liabilities and Other Liabilities
Patient prepayments, deposits and refunds payable	$ 24,183		$ 24,563
Accrued sales taxes and other taxes	8,543		6,810
Insurance and self-insurance accruals	8,033		8,886
Derivative liability	3,516		724
Accrued professional fees	2,533		3,751
Accrued interest payable	266		332
Other current liabilities	8,751		6,717
Total	$ 55,825	$ 50,431	$ 51,783