Mergers and Acquisitions - Schedule of Business Acquisition Pro Forma Information (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended
Jun. 30, 2014	Jun. 30, 2013
Business Combinations [Abstract]
Total Revenues	$ 234,357	$ 233,117
Net Income	$ 56,228	$ 60,337

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

Name:	us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration