Note 10. Employee Retirement Plans Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Retirement Benefits [Abstract]
Employer contributions	$ 1.0	$ 1.1
Defined Contribution Plan, Expected Future Employer Discretionary Contributions, Next Fiscal Year	18.5
Defined Contribution Plan, Employer Discretionary Contribution Amount	$ 11.4