Note 13 - Stock-based Compensation and Similar Arrangements - Stock Appreciation Rights, Fair Value Assumptions (Details) - Stock Appreciation Rights (SARs) [Member] |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Expected dividend yield | 0.00% | 0.00% | 0.00% |
| Minimum [Member] | |||
| Expected stock price volatility | 35.71% | 43.75% | 46.75% |
| Risk-free interest rate | 1.11% | 1.24% | 1.30% |
| Expected life of options (years) (Day) | 1 year | 2 years 273 days | 3 years 273 days |
| Maximum [Member] | |||
| Expected stock price volatility | 41.82% | 45.30% | 50.10% |
| Risk-free interest rate | 1.64% | 1.70% | 1.76% |
| Expected life of options (years) (Day) | 3 years | 4 years 273 days | 5 years 273 days |