Note 2 - Income (Loss) Per Share - Calculation of Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Numerator:
Net income	$ 9,971	$ 1,548	$ 14,388	$ 1,510
Denominator:
Basic weighted average shares outstanding (in shares)	18,337	18,281	18,334	18,269
Effect of dilutive securities:
Equivalent shares issuable upon conversion of unvested restricted stock (in shares)	104	78	90	78
Denominator for diluted earnings per share – adjusted weighted-average shares and assumed conversions (in shares)	18,441	18,359	18,424	18,347
Basic and diluted net income per share (in dollars per share)	$ 0.54	$ 0.08	$ 0.78	$ 0.08

The amount of net income or loss for the period per each share in instances when basic and diluted earnings per share are the same amount and reported as a single line item on the face of the financial statements. Basic earnings per share is the amount of net income or loss for the period per each share of common stock or unit outstanding during the reporting period. Diluted earnings per share includes the amount of net income or 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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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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