Acquisitions Schedule of Intangible Assets Acquired as Part of Business Combination (Details) - USD ($) $ in Thousands	Jun. 05, 2015	Apr. 14, 2015
Creative Circle [Member]
Acquired Intangible Assets [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	$ 194,500
Creative Circle [Member] | Trademarks [Member]
Acquired Intangible Assets [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	66,100
Creative Circle [Member] | Contractor Relations [Member]
Acquired Intangible Assets [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	29,500
Creative Circle [Member] | Customer relations
Acquired Intangible Assets [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	90,700
Creative Circle [Member] | Non-compete agreements
Acquired Intangible Assets [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	7,300
Creative Circle [Member] | Contract-Based Intangible Assets [Member]
Acquired Intangible Assets [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	$ 900
LabResource [Member]
Acquired Intangible Assets [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill		$ 7,528
LabResource [Member] | Trademarks [Member]
Acquired Intangible Assets [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill		1,140
LabResource [Member] | Contractor Relations [Member]
Acquired Intangible Assets [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill		947
LabResource [Member] | Customer relations
Acquired Intangible Assets [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill		5,421
LabResource [Member] | Non-compete agreements
Acquired Intangible Assets [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill		20
LabResource [Member] | Contract-Based Intangible Assets [Member]
Acquired Intangible Assets [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill		$ 0