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
Mar. 31, 2014	Mar. 31, 2013
Earnings Per Share [Abstract]
Income from continuing operations after income tax expense	$ 17,982	$ 17,121
Basic
Weighted average common shares outstanding	48,182	49,417
Diluted
Stock options	865	25
Restricted stock awards	414	342
Contingent shares	100	52
Convertible senior subordinated notes	3,057
Diluted weighted average common shares outstanding	52,618	49,836
Basic earnings per share from continuing operations	$ 0.37	$ 0.35
Diluted earnings per share from continuing operations	$ 0.34	$ 0.34
Conversion price of potential shares	$ 7.41

Incremental common shares attributable to restricted stock awards.

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Incremental common shares attributable to stock options.

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The price per share of the conversion feature embedded in the debt instrument.

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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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