Business Combinations - Results of Operations (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Weighted average number of shares outstanding:
Basic	140,915	141,139	141,253	140,925
Diluted	142,964	142,789	143,102	142,476
2014 Acquisitions [Member]
Business Acquisition, Pro Forma Information [Line Items]
Total revenues	$ 421,433	$ 400,738	$ 1,234,451	$ 1,138,466
Income before income taxes	112,687	109,069	318,806	320,089
Net income	$ 68,332	$ 65,985	$ 193,103	$ 193,404
Net income per share:
Basic	$ 0.47	$ 0.45	$ 1.33	$ 1.34
Diluted	$ 0.47	$ 0.45	$ 1.32	$ 1.32
Weighted average number of shares outstanding:
Basic	140,915	141,139	141,253	140,925
Diluted	142,964	142,789	143,102	142,476

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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

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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 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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