Note 1 - Significant Accounting Policies - Credit Risk and Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
|
| Allowance for credit losses, beginning of period | $ 9,898 | $ 9,692 | $ 9,114 |
| Additional provisions for the year | 417 | 206 | 1,233 |
| Uncollectible accounts written off or collected | (1,192) | 0 | (655) |
| Allowance for credit losses, end of period | $ 9,123 | $ 9,898 | $ 9,692 |
| X | ||||||||||
- Definition Amount of allowance for credit loss on accounts receivable. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
|
| X | ||||||||||
- Definition Amount of direct write-downs of accounts receivable charged against the allowance. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
|
| X | ||||||||||
- Definition Amount of expense (reversal of expense) for expected credit loss on accounts receivable. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
|