Acquisitions - Additional Information (Details) (USD $)			3 Months Ended
Sep. 30, 2014	Dec. 31, 2013	Jun. 30, 2014 Series of Business Acquisitions company	Sep. 30, 2014 Series of Business Acquisitions
Business Acquisition [Line Items]
Number of companies acquired			3
Aggregate purchase price			$ 39,400,000
Goodwill	$ 247,985,000	$ 231,838,000		$ 16,100,000

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 30

-Section 30

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Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 30

-Section 30

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-URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6613-128477

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=7488404&loc=d3e6927-128479

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