Segment Information (Schedule of Segment Revenues Before Reimbursements, Segment Total Revenues and Segment Operating Profit) (Details) (USD $) In Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Total revenues before reimbursements	$ 173,293	$ 154,617	$ 342,897	$ 308,487
Total revenues	194,408	172,323	383,207	345,873
Total combined segment operating profit	60,310	54,669	118,308	109,130
General and administrative expenses	31,143	29,089	63,552	59,549
Depreciation expense	3,206	3,553	6,583	7,354
Amortization expense	2,163	2,962	4,464	5,758
Long-term compensation expense related to consulting personnel (including share-based compensation)	3,839	2,180	7,048	5,001
Operating income	19,959	16,885	36,661	31,468
Other expense, net	1,554	3,153	2,991	6,423
Income before income tax expense	18,405	13,732	33,670	25,045
Business Consulting Services [Member]
Total revenues before reimbursements	71,710	63,430	142,179	120,829
Total revenues	81,193	71,756	160,820	138,006
Total combined segment operating profit	23,453	23,148	46,635	42,165
Dispute and Investigative Services [Member]
Total revenues before reimbursements	66,789	59,737	132,542	123,075
Total revenues	73,117	63,867	145,123	131,761
Total combined segment operating profit	27,279	21,585	53,056	46,993
Economic Consulting [Member]
Total revenues before reimbursements	18,475	16,966	36,349	33,954
Total revenues	19,889	18,622	38,428	37,231
Total combined segment operating profit	6,029	6,273	11,786	12,569
International Consulting [Member]
Total revenues before reimbursements	16,319	14,484	31,827	30,629
Total revenues	20,209	18,078	38,836	38,875
Total combined segment operating profit	$ 3,549	$ 3,663	$ 6,831	$ 7,403