Goodwill and Identifiable Assets (Goodwill) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Goodwill [Line Items]
Goodwill, Purchase Accounting Adjustments	$ 0	$ 0	$ 1,805
Goodwill [Roll Forward]
Gross goodwill	514,426us-gaap_GoodwillGross	444,084us-gaap_GoodwillGross
Accumulated impairment loss	0	0
Goodwill	514,426us-gaap_Goodwill	444,084us-gaap_Goodwill
Translation adjustment	(2,366)us-gaap_GoodwillTranslationAdjustments	811us-gaap_GoodwillTranslationAdjustments
Gross goodwill	512,060us-gaap_GoodwillGross	514,426us-gaap_GoodwillGross	444,084us-gaap_GoodwillGross
Accumulated impairment loss	0	0	0
Goodwill	512,060us-gaap_Goodwill	514,426us-gaap_Goodwill	444,084us-gaap_Goodwill
Goodwill	512,060us-gaap_Goodwill	514,426us-gaap_Goodwill	444,084us-gaap_Goodwill
CyberCoders [Member]
Goodwill [Roll Forward]
Goodwill, Acquired During Period		69,018
Apex
Goodwill [Roll Forward]
Gross goodwill	289,712	289,712
Accumulated impairment loss	0	0
Goodwill	289,712	289,712
Translation adjustment	(1,761)	0
Gross goodwill	287,951	289,712
Accumulated impairment loss	0	0
Goodwill	287,951	289,712
Goodwill	287,951	289,712
Oxford
Goodwill [Roll Forward]
Gross goodwill	220,150	150,619
Accumulated impairment loss	0	0
Goodwill	220,150	150,619
Goodwill, Other Changes		513
Translation adjustment	(120)	0
Gross goodwill	220,030	220,150
Accumulated impairment loss	0	0
Goodwill	220,030	220,150
Goodwill	220,030	220,150
Oxford \| CyberCoders [Member]
Goodwill [Roll Forward]
Goodwill, Acquired During Period		69,018
Life Sciences Europe [Member]
Goodwill [Roll Forward]
Gross goodwill	4,564	3,753
Accumulated impairment loss	0	0
Goodwill	4,564	3,753
Translation adjustment	(485)	811
Gross goodwill	4,079	4,564
Accumulated impairment loss		0
Goodwill	4,079	4,564
Goodwill	$ 4,079	$ 4,564

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

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Amount before 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.

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Amount of other (increase) decrease of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of increase (decrease) from adjustments after acquisition date under purchase accounting of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of increase (decrease) from foreign currency translation adjustments of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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