Segment Information (Tables)

12 Months Ended

Dec. 31, 2017

Segment Reporting Measurement Disclosures [Abstract]

Schedule of Segment Revenues before Reimbursements, Segment Total Revenues and Segment Operating Profit

	For the year ended
	December 31,
	2017		2016		2015
Revenues before reimbursements:
Healthcare	$	370,266	$	354,268	$	288,798
Energy		124,492		115,940		106,023
Financial Services Advisory and Compliance		140,336		152,166		124,359
Disputes, Forensics and Legal Technology		304,545		316,372		314,628
Total revenues before reimbursements	$	939,639	$	938,746	$	833,808
Total revenues:
Healthcare	$	404,120	$	389,233	$	313,884
Energy		146,425		133,612		124,491
Financial Services Advisory and Compliance		159,410		173,391		142,959
Disputes, Forensics and Legal Technology		322,372		338,244		338,152
Total revenues	$	1,032,327	$	1,034,480	$	919,486
Segment operating profit:
Healthcare	$	111,188	$	115,163	$	90,869
Energy		33,783		32,637		31,380
Financial Services Advisory and Compliance		53,772		63,464		49,130
Disputes, Forensics and Legal Technology		97,564		108,685		102,449
Total segment operating profit		296,307		319,949		273,828
Segment reconciliation to income before income tax expense:
Reconciling items:
General and administrative expenses		166,922		168,954		147,462
Depreciation expense		28,826		27,742		23,612
Amortization expense		8,960		11,507		8,613
Other operating costs (benefit), net		4,220		1,872		(9,900	)
Long-term compensation expense attributable to client-service employees (including    share-based compensation expense)		11,254		13,138		11,914
Operating income		76,125		96,736		92,127
Interest and other expense, net		5,544		3,325		3,974
Income before income tax expense	$	70,581	$	93,411	$	88,153

Total Assets by Segment

	December 31,		December 31,
	2017		2016
Healthcare	$	399,268	$	391,859
Energy		115,478		120,311
Financial Services Advisory and Compliance		95,534		98,846
Disputes, Forensics and Legal Technology		343,248		330,239
Unallocated assets		126,736		113,542
Total assets	$	1,080,264	$	1,054,797

Schedule of Revenue by Geographic Region

	For the year ended
	December 31,
	2017		2016		2015
Total revenue:
United States	$	931,649	$	938,224	$	833,527
United Kingdom		50,700		55,626		62,099
Other		49,978		40,630		23,860
Total	$	1,032,327	$	1,034,480	$	919,486

Schedule of Assets by Geographic Region

	December 31,		December 31,
Total assets:	2017		2016
United States	$	966,547	$	952,572
United Kingdom		64,463		62,156
Other		49,254		40,069
Total	$	1,080,264	$	1,054,797