Business Combinations - Pro Forma Consolidated Results of Operations (Detail) (Consolidated Entities [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Consolidated Entities [Member]
Business Acquisitions Pro Forma Infomation [Line Items]
Consolidated pro forma revenue	$ 194,764	$ 196,474	$ 390,052	$ 381,443
Consolidated pro forma income from continuing operations	$ 14,733	$ 22,644	$ 35,996	$ 46,514

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.

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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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration