Supplemental Condensed Consolidating Guarantor and Non-Guarantor Financial Information (Condensed Consolidating Statement Of Comprehensive Income (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Revenues	$ 446,344,000	$ 470,285,000
Operating expenses
Direct cost of revenues	309,072,000	305,636,000
Selling, general and administrative expenses	107,295,000	103,609,000
Special charges	0	5,061,000
Acquisition-related contingent consideration	395,000	1,134,000
Amortization of other intangible assets	2,493,000	2,606,000
Costs and Expenses, Total	419,255,000	418,046,000
Operating income	27,089,000	52,239,000
Other (expense) income	(5,196,000)	(3,672,000)
Income before income tax provision	21,893,000	48,567,000
Income tax (benefit) provision	7,877,000	18,386,000
Net income	14,016,000	30,181,000
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments, net of tax expense of $0	7,370,000	(358,000)
Total other comprehensive income (loss), net of tax	7,370,000	(358,000)
Comprehensive income	21,386,000	29,823,000
FTI Consulting
Revenues	151,807,000	182,994,000
Operating expenses
Direct cost of revenues	111,258,000	114,429,000
Selling, general and administrative expenses	45,798,000	44,667,000
Acquisition-related contingent consideration		6,000
Amortization of other intangible assets	902,000	986,000
Costs and Expenses, Total	157,958,000	160,088,000
Operating income	(6,151,000)	22,906,000
Other (expense) income	(5,252,000)	(5,077,000)
Income before income tax provision	(11,403,000)	17,829,000
Income tax (benefit) provision	(5,583,000)	8,149,000
Equity in net earnings of subsidiaries	19,836,000	20,501,000
Net income	14,016,000	30,181,000
Other comprehensive income (loss), net of tax:
Comprehensive income	14,016,000	30,181,000
Guarantor Subsidiaries
Revenues	171,026,000	162,563,000
Operating expenses
Direct cost of revenues	117,786,000	109,190,000
Selling, general and administrative expenses	30,984,000	30,721,000
Special charges		4,563,000
Acquisition-related contingent consideration	395,000	1,128,000
Amortization of other intangible assets	540,000	558,000
Costs and Expenses, Total	149,705,000	146,160,000
Operating income	21,321,000	16,403,000
Other (expense) income	(427,000)	(710,000)
Income before income tax provision	20,894,000	15,693,000
Income tax (benefit) provision	10,918,000	6,859,000
Equity in net earnings of subsidiaries	8,573,000	9,882,000
Net income	18,549,000	18,716,000
Other comprehensive income (loss), net of tax:
Comprehensive income	18,549,000	18,716,000
Non-Guarantor Subsidiaries
Revenues	126,103,000	127,066,000
Operating expenses
Direct cost of revenues	82,561,000	84,315,000
Selling, general and administrative expenses	30,572,000	28,261,000
Special charges		498,000
Amortization of other intangible assets	1,770,000	1,879,000
Costs and Expenses, Total	114,903,000	114,953,000
Operating income	11,200,000	12,113,000
Other (expense) income	483,000	2,115,000
Income before income tax provision	11,683,000	14,228,000
Income tax (benefit) provision	2,542,000	3,378,000
Net income	9,141,000	10,850,000
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments, net of tax expense of $0	7,370,000	(358,000)
Total other comprehensive income (loss), net of tax	7,370,000	(358,000)
Comprehensive income	16,511,000	10,492,000
Eliminations
Revenues	(2,592,000)	(2,338,000)
Operating expenses
Direct cost of revenues	(2,533,000)	(2,298,000)
Selling, general and administrative expenses	(59,000)	(40,000)
Amortization of other intangible assets	(719,000)	(817,000)
Costs and Expenses, Total	(3,311,000)	(3,155,000)
Operating income	719,000	817,000
Income before income tax provision	719,000	817,000
Equity in net earnings of subsidiaries	(28,409,000)	(30,383,000)
Net income	(27,690,000)	(29,566,000)
Other comprehensive income (loss), net of tax:
Comprehensive income	$ (27,690,000)	$ (29,566,000)