Note 2 - Summary of Significant Accounting Policies - Analysis of Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands |
12 Months Ended | |||
|---|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
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| Balance at beginning of year | $ 4,989 | $ 4,737 | ||
| Charged to costs and expenses | 5,641 | 5,631 | ||
| Deductions | [1] | (4,116) | (5,379) | |
| Balance at end of year | $ 6,514 | $ 4,989 | ||
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| X | ||||||||||
- Definition A valuation allowance for trade and other receivables due to an Entity within one year (or the normal operating cycle, whichever is longer) that are expected to be uncollectible. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of direct write-downs of accounts receivable charged against the allowance. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of expense related to write-down of receivables to the amount expected to be collected. Includes, but is not limited to, accounts receivable and notes receivable. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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