Consolidated Statements of Stockholders' Equity (Parentheticals) - Additional Paid-in Capital [Member] - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Exercise of employee stock option, tax benefit | $ 2,706 | $ 2,683 | |
| Exercise of employee stock option, tax shortfall | $ 276 | ||