Summary of Significant Accounting Policies - Computation of Basic and Diluted Earnings Per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Numerator:
Income from continuing operations	$ 5,785	$ 4,389
Income from discontinued operations, net of tax	0	1,860
Net income	$ 5,785us-gaap_NetIncomeLoss	$ 6,249us-gaap_NetIncomeLoss
Denominator:
Weighted average shares outstanding – basic	28,276	32,969
Common stock equivalents	199	199
Weighted average shares outstanding – diluted	28,475	33,168
Earnings per share – basic:
From continuing operations	$ 0.20	$ 0.13
From discontinued operations	$ 0.00	$ 0.06
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Earnings per share – diluted:
From continuing operations	$ 0.20	$ 0.13
From discontinued operations	$ 0.00	$ 0.06
Earnings per share – diluted	$ 0.20us-gaap_EarningsPerShareDiluted	$ 0.19us-gaap_EarningsPerShareDiluted

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 of income (loss) from continuing operations attributable to the parent. Also defined as revenue less expenses and taxes from ongoing operations before extraordinary items but after deduction of those portions of income or loss from continuing operations that are allocable to noncontrolling interests.

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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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