Unaudited Pro Forma Results (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended	6 Months Ended
Sep. 30, 2012	Sep. 30, 2012
Business Combinations [Abstract]
Revenues	$ 222,665	$ 431,124
Net Income	$ 22,286	$ 37,193
Earnings per share - basic	$ 0.46	$ 0.77
Earnings per share - diluted	$ 0.46	$ 0.76
Weighted Average Shares Outstanding:
Basic	48,196,225	48,158,499
Diluted	48,803,778	48,669,224

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Business Acquisitions, Pro Forma, Weighted Average Number of Shares Outstanding, Basic

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The pro forma basic net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.

+ References

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

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-Name Statement of Financial Accounting Standard (FAS)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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The pro forma diluted net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.

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The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period.

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The pro forma revenue for a period as if the business combination or combinations had been completed at the beginning of the period.

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