Acquisitions - Summary of Unaudited Pro Forma Information (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Business Combinations [Abstract]
Revenues	$ 381,246	$ 392,392	$ 764,155	$ 777,016
Net income	$ 34,756	$ 3,942	$ 53,995	$ 854
Basic earnings per share	$ 0.17	$ 0.02	$ 0.27	$ 0.01
Basic weighted average number of common shares outstanding	198,765	170,810	198,143	169,674
Diluted earnings per share	$ 0.17	$ 0.02	$ 0.26	$ 0.00
Diluted weighted average number of common and common equivalent shares outstanding	204,916	179,104	204,596	177,974

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.

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=65885119&loc=d3e1392-128463

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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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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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