Revenue - (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020 USD ($) pharmacy	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) pharmacy	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
CONCENTRATION
Number of specialty pharmacies | pharmacy	2		2
Allowance for doubtful accounts	$ 4,600		$ 4,600		$ 3,900
Change in estimate of uncollectible (percent)			0.50%
Change in revenue recognized due to 0.5% change in uncollectible percentage			$ 200
Increase (decrease) to revenues	31,020	$ 30,499	77,712	$ 78,460
Other revenue	1,238	0	1,238	0
Other | Provider or Facility
CONCENTRATION
Other revenue	1,238	0	1,238	0
Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
CONCENTRATION
Increase (decrease) to revenues	8	$ 656	695	$ 353
COVID-19 potential impacts
CONCENTRATION
Allowance for doubtful accounts	$ 100		$ 100