Basis of Presentation and Consolidation - Computation of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Numerator
Numerator for basic and diluted (loss) earnings per share - (loss) income from continuing operations available to common stockholders	$ (6,215)	$ 8,821	$ (17,806)	$ 15,801
Denominator
Denominator for basic earnings per share - weighted average shares outstanding (in shares)	50,282	50,165	50,259	50,133
Effect of dilutive securities - stock options and other stock units (in shares)	0	197	0	237
Denominator for diluted earnings per share - adjusted weighted average shares outstanding (in shares)	50,282	50,362	50,259	50,370
(Loss) Earnings per share:
Basic (in dollars per share)	$ (0.12)	$ 0.18	$ (0.35)	$ 0.32
Diluted (in dollars per share)	$ (0.12)	$ 0.18	$ (0.35)	$ 0.31
Diluted securities excluded from EPS amount (in shares)	71	0	104	0

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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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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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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Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

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