Goodwill and Intangible Assets, Changes in the Carrying Amount of Goodwill (Details) $ in Thousands	6 Months Ended
Jun. 30, 2015 USD ($)
Goodwill and Intangible Assets [Abstract]
Balance at December 31, 2014	$ 236,130
Preliminary purchase price allocations for acquisitions (Note 7)	18,179
Effect of foreign currency adjustments and other	880
Balance at June 30, 2015	$ 255,189

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

Name:	us-gaap_Goodwill
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant