Stock-Based Compensation - Fair Value of SAR's Using Black-Scholes Option-Pricing Model (Details) - Black Scholes - Stock appreciation rights - $ / shares |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Estimated fair value of SAR grant using Black-Scholes options pricing model | |||
| Dividend yield | 0.00% | 0.00% | 0.00% |
| Weighted average risk-free interest rate, Minimum | 1.10% | 1.40% | 1.50% |
| Weighted average risk-free interest rate, Maximum | 1.40% | 1.60% | 1.80% |
| Weighted average expected volatility | 40.00% | 40.00% | 40.00% |
| Expected life in years | 6 years 3 months | 6 years 3 months | 6 years 3 months |
| Minimum | |||
| Estimated fair value of SAR grant using Black-Scholes options pricing model | |||
| The weighted average fair value of stock appreciation rights issued (in dollars per share) | $ 2.79 | $ 3.33 | $ 4.18 |
| Maximum | |||
| Estimated fair value of SAR grant using Black-Scholes options pricing model | |||
| The weighted average fair value of stock appreciation rights issued (in dollars per share) | $ 3.74 | $ 3.90 | $ 4.93 |