Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SEC Schedule, 12-09, Allowance, Credit Loss
Accounts receivable allowance
Balance at Beginning of Year	$ 13,683	$ 14,799	$ 10,772
Provision	22,289	20,453	20,233
Recoveries	0	0	0
Charge-offs	(18,890)	(21,569)	(16,206)
Balance at End of Year	17,082	13,683	14,799
Estimated liability for appeals
Balance at Beginning of Year	13,683	14,799	10,772
Provision	22,289	20,453	20,233
Appeals found in providers favor	0	0	0
Release of estimated liability	(18,890)	(21,569)	(16,206)
Balance at End of Year	17,082	13,683	14,799
Estimated Liability for Appeals and Estimated Allowance for Appeals
Accounts receivable allowance
Balance at Beginning of Year	0	8,544	11,126
Provision	0	0	83
Recoveries	0	(108)	(2,665)
Charge-offs	0	(8,436)	0
Balance at End of Year	0	0	8,544
Estimated liability for appeals
Balance at Beginning of Year	0	8,544	11,126
Provision	0	0	83
Appeals found in providers favor	0	(108)	(2,665)
Release of estimated liability	0	(8,436)	0
Balance at End of Year	$ 0	$ 0	$ 8,544