Note 4 - Income Taxes - Income Positions (Details) |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Mar. 31, 2022 |
Mar. 31, 2021 |
Mar. 31, 2022 |
Mar. 31, 2021 |
|
| Effective tax rate | 26.10% | 25.20% | 26.60% | 24.80% |
| Effective tax rate excluding LLC impairment | 24.00% | 23.70% | ||
| Effective Income Tax Rate, Including the Effect of Impaired Investment [Member] | ||||
| Effective tax rate - LLC impairment | 25.70% | 0.00% | 25.70% | 0.00% |
| Effective Income Tax Rate, Excluding the Effect of Impaired Investment [Member] | ||||
| Effective tax rate excluding LLC impairment | 24.00% | 25.20% | 23.70% | 24.80% |