Income Taxes - Narrative (Details) $ in Millions	3 Months Ended
	Mar. 31, 2021 USD ($)
Domestic Tax Authority
Income Taxes
Operating loss carryforwards	$ 1,700.0
Operating loss carryforwards, subject to expiration	800.0
Operating loss carryforwards, not subject to expiration	900.0
Tax credit carryforward, amount	$ 33.5
Minimum
Income Taxes
Number of tax years open for state tax audit (in years)	3 years
Maximum
Income Taxes
Number of tax years open for state tax audit (in years)	5 years