Earnings and Dividends per Share - Number of Shares Outstanding for Calculation of Earnings Per Share (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Numerator (for basic and diluted earnings (loss) per share)
Net income (loss)	$ 5,515	$ (901)	$ 7,379	$ 4,862
Denominator
Basic weighted-average shares outstanding	34,923,587	34,669,810	34,879,811	34,631,519
Common stock equivalents arising from stock options and restricted stock awards	659,000		592,000	83,000
Diluted weighted-average shares outstanding	35,582,727	34,669,810	35,471,628	34,715,141

Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

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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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