Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands |
Dec. 31, 2015 |
Dec. 31, 2014 |
|---|---|---|
| Current Assets: | ||
| Allowance for doubtful accounts | $ 13,133 | $ 10,960 |
| Class A Common Stock | ||
| Shareholders' Investment: | ||
| Par or stated value per share (usd per share) | $ 1 | $ 1 |
| Shares authorized (shares) | 50,000,000 | 50,000,000 |
| Shares issued (shares) | 30,537,000 | 30,497,000 |
| Shares outstanding (shares) | 30,537,000 | 30,497,000 |
| Class B Common Stock | ||
| Shareholders' Investment: | ||
| Par or stated value per share (usd per share) | $ 1 | $ 1 |
| Shares authorized (shares) | 50,000,000 | 50,000,000 |
| Shares issued (shares) | 24,690,000 | 24,690,000 |
| Shares outstanding (shares) | 24,690,000 | 24,690,000 |