Subsequent Events - Pro Forma 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:
Net Income	$ 12,889us-gaap_ProfitLoss	$ 16,911us-gaap_ProfitLoss
Earnings per share:
Outstanding common stock equivalents having no dilutive effect	79	44
Pro Forma [Member]
Numerator:
Net Income	$ 12,889	$ 16,911
Denominator:
Weighted average basic share	28,218	26,712
Dilutive potential common shares	534	672
Weighted average fully dilutive shares	28,752	27,384
Earnings per share:
Basic	$ 0.46	$ 0.63
Diluted	$ 0.45	$ 0.62
Outstanding common stock equivalents having no dilutive effect	237	132

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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Pro forma basic earnings per share or earnings per unit, which is commonly presented in initial public offerings based on the terms of the offering.

+ References

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Pro forma diluted earnings per share, which is commonly presented in initial public offerings.

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The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

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The weighted average number of shares or units and dilutive common stock or unit equivalents outstanding in the calculation of proforma diluted earnings per share (earnings per unit), which is commonly presented in initial public offerings based on the terms of the offering.

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The weighted average number of shares (units) outstanding in the calculation of pro forma basic earnings per share (earnings per unit), which is commonly presented in initial public offerings based on the terms of the offering.

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