Note 7 - Earnings Per Share - Dilutive Effect of Stock Options and Awards (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Net income	$ 10,177	$ 9,891
Basic (in shares)	18,972	18,994
Dilutive effect of stock options, RSUs, and PSAs (in shares)	451	279
Weighted-average number of diluted shares outstanding during the period (in shares)	19,423	19,273
Basic (in dollars per share)	$ 0.54	$ 0.52
Diluted (in dollars per share)	$ 0.52	$ 0.51

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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