Business Combinations - Results of Operations (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2014	Mar. 31, 2013
Weighted average number of shares outstanding:
Basic	141,610	140,796
Diluted	143,309	142,947
2014 Acquisitions [Member]
Business Acquisition, Pro Forma Information [Line Items]
Total revenues	$ 363,739	$ 335,253
Income before income taxes	86,883	99,566
Net income	$ 52,443	$ 60,176
Net income per share:
Basic	$ 0.36	$ 0.42
Diluted	$ 0.36	$ 0.41
Weighted average number of shares outstanding:
Basic	141,610	140,796
Diluted	143,309	142,947

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The pro forma income from continuing operations before changes in accounting and extraordinary items, net of tax effect per basic share of common stock for a period as if the business combination or combinations had been completed at the beginning of a period.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 50

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The pro forma income from continuing operations before changes in accounting and extraordinary items, net of tax effect, 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 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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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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+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 260

-SubTopic 10

-Section 50

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