Earnings Per Common Share - Details of Earnings Per Share Calculations (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Earnings Per Share [Abstract]
Net income from continuing operations	$ 13,866	$ 6,893	$ 27,523	$ 10,419
Income (loss) from discontinued operations	(14)	(7)	(37)	(22)
Net income	$ 13,852	$ 6,886	$ 27,486	$ 10,397
Basic income (loss) per share
Continuing	$ 0.35	$ 0.18	$ 0.69	$ 0.26
Discontinued	0.00	0.00	0.00	0.00
Total	0.35	0.18	0.69	0.26
Diluted income (loss) per share
Continuing	0.35	0.17	0.69	0.26
Discontinued	0.00	0.00	0.00	0.00
Total	$ 0.35	$ 0.17	$ 0.69	$ 0.26
Weighted average common shares outstanding:
Basic	39,580	39,358	39,554	39,315
Diluted	39,738	39,471	39,699	39,430

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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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This element represents the income or loss from continuing operations attributable to the economic entity which may also be defined as revenue less expenses and taxes from ongoing operations before extraordinary items, and noncontrolling interest.

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The amount of net income (loss) from continuing operations per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) derived from continuing operations during 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 of income (loss) from a disposal group, net of income tax, reported as a separate component of income before extraordinary items after deduction or consideration of the amount allocable to noncontrolling interests. Includes, net of tax, income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal.

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Per basic share amount, after tax, of income (loss) from the day-to-day business activities of the discontinued operation and gain (loss) from the disposal of the discontinued operation.

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Per diluted share amount, after tax, of income (loss) from the day-to-day business activities of the discontinued operation and gain (loss) from the disposal of the discontinued operation.

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