Note 7 - Retirement Plans (Details Textual) - USD ($) $ in Millions |
9 Months Ended | 12 Months Ended |
---|---|---|
Sep. 30, 2021 |
Dec. 31, 2020 |
|
Defined Contribution Plan, Expected Contributions, Remainder of Fiscal Year | $ 2 | |
Profit Sharing Contribution [Member] | ||
Defined Contribution Plan, Employer Discretionary Contribution Amount | 11 | $ 7 |
Pension Plan [Member] | Gray Pension Plan [Member] | ||
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year | $ 4 |