Segment Information - Components of Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Components of Segment Information
Operating income (loss)	$ 13,699	$ 20,576	$ (16,198)	$ 45,207
Revenue from Contract with Customer, Including Assessed Tax	205,304	219,289	645,780	644,488
Reimbursable Revenues	2,860	23,636	25,133	65,787
Total revenues and reimbursable expenses	208,164	242,925	670,913	710,275
Gain (Loss) Related To Litigation Settlement And Other Operating Gains	0	630	150	1,571
Depreciation and amortization	6,176	6,962	18,483	21,285
Goodwill, Impairment Loss	0	0	59,816	0
Other expense, net	(224)	(4,456)	(6,829)	(10,326)
Income from continuing operations before income tax expense	13,475	16,120	(23,027)	34,881
Healthcare
Components of Segment Information
Revenue from Contract with Customer, Including Assessed Tax	87,406	100,000	268,340	295,621
Goodwill, Impairment Loss			0
Business Advisory
Components of Segment Information
Revenue from Contract with Customer, Including Assessed Tax	66,048	62,519	201,423	183,602
Goodwill, Impairment Loss			(59,816)
Education [Member]
Components of Segment Information
Revenue from Contract with Customer, Including Assessed Tax	51,850	56,770	176,017	165,265
Goodwill, Impairment Loss			0
Operating Segments
Components of Segment Information
Operating income (loss)	48,938	59,218	149,929	170,290
Revenue from Contract with Customer, Including Assessed Tax	205,304	219,289	645,780	644,488
Reimbursable Revenues	2,860	23,636	25,133	65,787
Total revenues and reimbursable expenses	208,164	242,925	670,913	710,275
Operating Segments | Healthcare
Components of Segment Information
Operating income (loss)	$ 25,610	$ 32,863	$ 70,831	$ 94,058
Segment operating income as a percentage of segment revenues	29.30%	32.90%	26.40%	31.80%
Revenue from Contract with Customer, Including Assessed Tax	$ 87,406	$ 100,000	$ 268,340	$ 295,621
Operating Segments | Business Advisory
Components of Segment Information
Operating income (loss)	$ 10,780	$ 11,942	$ 37,306	$ 32,997
Segment operating income as a percentage of segment revenues	16.30%	19.10%	18.50%	18.00%
Revenue from Contract with Customer, Including Assessed Tax	$ 66,048	$ 62,519	$ 201,423	$ 183,602
Operating Segments | Education [Member]
Components of Segment Information
Operating income (loss)	$ 12,548	$ 14,413	$ 41,792	$ 43,235
Segment operating income as a percentage of segment revenues	24.20%	25.40%	23.70%	26.20%
Revenue from Contract with Customer, Including Assessed Tax	$ 51,850	$ 56,770	$ 176,017	$ 165,265
Segment Reconciling Items
Components of Segment Information
Other operating expenses	29,042	32,310	87,826	105,369
Gain (Loss) Related To Litigation Settlement And Other Operating Gains	0	(630)	(150)	(1,571)
Depreciation and amortization	6,197	6,962	18,635	21,285
Goodwill, Impairment Loss			59,816
Other expense, net	$ 224	$ 4,456	$ 6,829	$ 10,326