Note 7 - Income Taxes (Details Textual) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2022 |
Dec. 31, 2021 |
Dec. 31, 2020 |
|
| Deferred Tax Assets, Valuation Allowance, Total | $ 0 | $ 0 | |
| Income Tax Examination, Penalties and Interest Accrued Liabilities (Receivables) | (3,000) | (1,000) | |
| Income Tax Examination, Penalties and Interest Expense (Benefit) | (2,000) | (5,000) | $ 5,000 |
| Unrecognized Tax Benefits that Would Impact Effective Tax Rate | 31,000 | 31,000 | $ 52,000 |
| State and Local Jurisdiction [Member] | Nebraska, Iowa, Arkansas, and Idaho Department of Revenue [Member] | |||
| Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability | $ (95,000) | ||
| State and Local Jurisdiction [Member] | Nebraska, Oklahoma, Idaho, Louisiana and Arkansas Department of Revenue [Member] | |||
| Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability | $ (32,000) | ||