Income Taxes Reconciliation of Statutory Federal Income Tax Rate and Effective Tax Rate Footnotes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Loss Carryforwards [Line Items]
Federal statutory income tax rate	21.00%	21.00%	21.00%	35.00%
Disallowed officer compensation	$ 1.9	$ 6.1
Share based compensation shortfalls	3.6	4.0
Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations	0.0	19.0
Operating Loss Carryforwards		75.7
Alternative minimum tax		126.0
Deferred Tax Assets, Tax Credit Carryforwards		50.3
Remeasurement Of Deferred Taxes Due To NOL Carrybacks	$ 61.0
Louisiana [Member]
Operating Loss Carryforwards [Line Items]
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount		$ 25.3	$ 25.5