Computation of Earnings Per Share - Calculation of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Numerator
Net income	$ 7,179	$ 3,698
Determination of shares
Weighted-average common shares outstanding	4,917	5,008
Dilutive effect - share-based awards	19	9
Diluted weighted-average common shares outstanding	4,936	5,017
Earnings per common share
Basic	$ 1.46	$ 0.74
Diluted	$ 1.45	$ 0.74

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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- Definition

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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- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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