Earnings Per Share - Computation of Basic and Diluted Earnings Per Share for Continuing Operations (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended	12 Months Ended
Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Numerator:
Income from continuing operations	$ (1,378)	$ 7,320	$ 6,446	$ 18,026	$ (2,910)	$ 5,592	$ 5,603	$ 17,094	$ 30,414	$ 25,379	$ 23,793
Basic
Weighted average common shares outstanding	48,455	48,451	48,273	48,182	46,681	48,504	49,639	49,417	48,343	48,632	49,002
Diluted
Stock options									761	194
Restricted stock awards									293	263	186
Contingent shares									129	52	64
Convertible senior subordinated notes									1,961
Diluted weighted average common shares outstanding	48,455	51,209	52,052	52,618	46,981	49,003	49,929	49,836	51,487	49,141	49,252
Basic earnings per share from continuing operations	$ (0.03)	$ 0.15	$ 0.13	$ 0.37	$ (0.06)	$ 0.12	$ 0.11	$ 0.35	$ 0.63	$ 0.52	$ 0.49
Diluted earnings per share from continuing operations	$ (0.03)	$ 0.14	$ 0.12	$ 0.34	$ (0.06)	$ 0.11	$ 0.11	$ 0.34	$ 0.59	$ 0.52	$ 0.48

Incremental common shares attributable to restricted stock awards.

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Incremental common shares attributable to stock options.

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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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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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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of contingently issuable shares. Contingently issuable shares are those shares that are issuable for little or no cash contingent on certain conditions being met.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of convertible debt securities using the if-converted 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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