Acquisitions and Dispositions - Narrative (Details) £ in Thousands, $ in Thousands			3 Months Ended								9 Months Ended	12 Months Ended
	Sep. 16, 2016 GBP (£)	Oct. 06, 2015 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Mar. 20, 2015
Business Acquisition [Line Items]
Operating profit (loss)			$ (2,281)	$ (17,921)	$ (6,460)	$ (3,821)	$ (8,810)	$ (22,129)	$ 1,203	$ 1,140		$ (30,483)	$ (28,596)	$ 5,386
Proceeds from disposition of business interests, net of cash disposed												5,849	430	0
Loss on disposition of business interests			$ 0	$ 11,301	$ 0	$ 0	$ 0	$ 0	$ 0	$ 310		11,301	310	0
EdgeRock Technologies, LLC [Member]
Business Acquisition [Line Items]
Cash consideration paid to acquire business		$ 33,400
CDI-Pycopsa Ingenieria y Construccion [Member]
Business Acquisition [Line Items]
Proceeds from disposition of business interests, net of cash disposed												132	430
Loss on disposition of business interests													310
Ownership percentage															67.00%
Specialty Talent and Technology [Member]
Business Acquisition [Line Items]
Operating profit (loss)												800
Enterprise Talent [Member]
Business Acquisition [Line Items]
Operating profit (loss)												$ (7,504)	$ (1,448)	$ 24,594
Enterprise Talent [Member] | CDI AndersElite Limited Disposition [Member] | Disposed of by Sale [Member]
Business Acquisition [Line Items]
Proceeds from disposition of business interests, net of cash disposed | £	£ 4,500
Consideration received, subordinated debt | £	£ 1,750
Consideration received, percent of equity in Holdings	19.99%
Value of non-cash purchase consideration received | £	£ 500
Loss on disposition of business interests											$ 11,300