Acquisitions - Pro forma Combined Revenues and Net Income (Detail) (All Business Combinations [Member], USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended	6 Months Ended
Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
All Business Combinations [Member]
Business Acquisition [Line Items]
Revenues	$ 569,233	$ 180,013	$ 885,417	$ 452,732
Net income (loss)	$ 143,232	$ (1,719)	$ 174,415	$ 59,635
Net income (loss) per share - basic	$ 3.82	$ (0.05)	$ 4.65	$ 1.62
Net income (loss) per share - diluted	$ 3.75	$ (0.05)	$ 4.57	$ 1.58

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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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (h)(2)-(3)

-URI http://asc.fasb.org/extlink&oid=25497992&loc=d3e1392-128463

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- Definition

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.

+ References

+ Details

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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.

+ References

+ Details

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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.

+ References

+ Details

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