Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Operating Loss Carryforwards [Line Items]
Income tax adjustment	$ 13,000	$ 27,900
Rate change - decrease in valuation allowance	367,963	380,990
Gross unrecognized tax benefits	18,100	18,400
Penalties and interest accrued	100	100
Deferred Tax Asset, Operating Loss Carryforwards
Operating Loss Carryforwards [Line Items]
Change in valuation allowance	82,200
Securities Purchase Agreement | HCA Healthcare, Inc. | Health Care Services
Operating Loss Carryforwards [Line Items]
Change in valuation allowance	(95,200)
Federal
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	808,700	812,000
Operating loss carryforwards, indefinite lived	335,800	181,100
State
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	2,200	2,300
Federal and state
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards valuation allowance	315,300	328,400
Tax credit valuation allowance	50,400	$ 50,300
Capital loss carryforward | Federal and state
Operating Loss Carryforwards [Line Items]
Tax credit valuation allowance	$ 2,200