The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
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-Section 45
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Goodwill And Intangible Assets, Net (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016	May 31, 2016
Goodwill [Line Items]
Adjustments	$ 2,659		$ (200)
Acquisitions			10,179
Amortization expense	$ 2,319	$ 2,921
Maximum [Member]
Goodwill [Line Items]
Estimated remaining useful lives	8 years
Disputes, Forensics & Legal Technology [Member]
Goodwill [Line Items]
Adjustments	$ (38)		(153)
Acquisitions
Percentage of fair value of reporting unit in excess of carrying value				17.00%
Healthcare [Member]
Goodwill [Line Items]
Adjustments	(43)		(12)
Acquisitions			8,057
Percentage of fair value of reporting unit in excess of carrying value				22.00%
Energy [Member]
Goodwill [Line Items]
Adjustments	2,749
Acquisitions			2,122
Percentage of fair value of reporting unit in excess of carrying value				32.00%
Financial Services Advisory and Compliance [Member]
Goodwill [Line Items]
Adjustments	(9)		(35)
Acquisitions
Percentage of fair value of reporting unit in excess of carrying value				61.00%
Ecofys Investments B.V. [Member]
Goodwill [Line Items]
Adjustments	$ 2,700