Income Taxes - NOLs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2020
Income Taxes
Net operating losses subject to Section 382 and other restrictions	$ 652.6
Federal
Income Taxes
Net operating loss carryforwards		$ 915.0
Net operating loss carryforward, Indefinite lived		262.4
Net operating loss carryforward subject to expiration		652.6
State
Income Taxes
Net operating loss carryforwards		990.8
Net operating loss carryforward, Indefinite lived		222.6
Net operating loss carryforward subject to expiration		768.2
Net operating loss carryforward subject to utilization limitations due to ownership change		$ 625.5