Earnings Per Common Share - Schedule of Earnings Per Share (Detail) - 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
Earnings Per Share [Abstract]
Earnings from continuing operations	$ 13,823	$ 14,551	$ 23,985	$ 22,268
Less dividend equivalents attributable to RSUs outstanding	(191)	(194)	(365)	(319)
Earnings from continuing operations attributable to common shareholders	13,632	14,357	23,620	21,949
Earnings (loss) from discontinued operations	(283)	555	(413)	2,542
(Loss) earnings from discontinued operations attributable to common shareholders	(283)	555	(413)	2,542
Net earnings attributable to common shareholders used for basic and diluted earnings per share calculation	$ 13,349	$ 14,912	$ 23,207	$ 24,491
Basic	39,901	34,634	39,806	34,594
Incremental shares from share based compensation	13		11
Diluted	39,914	34,634	39,817	34,594
Basic earnings per common share	$ 0.33	$ 0.43	$ 0.58	$ 0.71
Diluted earnings per common share	$ 0.33	$ 0.43	$ 0.58	$ 0.71

The income (loss) from continuing operations attributable to common stockholders.

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The income (loss) from discontinued operations that is attributable to common stockholders.

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The net income loss available to common stockholders used for basic and diluted earnings per share calculations.

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Amount of paid and unpaid cash, stock, and paid-in-kind (PIK) dividends declared and applicable to holders of share-based compensation, for example, but not limited to, non-vested shares, stock options, or restricted stock units.

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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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Amount after tax of income (loss) from continuing operations attributable to the parent.

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Amount after tax of income (loss) from a discontinued operation including the portion attributable to the noncontrolling interest. Includes, but is not limited to, the income (loss) from operations during the phase-out period, gain (loss) on disposal, gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and adjustments to a prior period gain (loss) on disposal.

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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 average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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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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