Supplemental Condensed Consolidating Guarantor and Non-Guarantor Financial Information Condensed Consolidating Balance Sheet (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Assets
Cash and cash equivalents	$ 120,959	$ 216,158	$ 114,451	$ 149,760
Accounts receivable, net	526,180	474,897
Other current assets	89,997	92,116
Total current assets	737,136	783,171
Property and equipment, net	59,474	61,856
Goodwill	1,183,627	1,180,001
Other intangible assets, net	49,895	52,120
Other assets	142,430	148,220
Total assets	2,172,562	2,225,368
Liabilities
Other current liabilities	293,328	378,455
Total current liabilities	293,328	378,455
Long-term debt, net	402,717	365,528
Other liabilities	279,988	274,027
Total liabilities	976,033	1,018,010
Stockholders' equity	1,196,529	1,207,358
Total liabilities and stockholders' equity	2,172,562	2,225,368
FTI Consulting
Assets
Cash and cash equivalents	18,371	47,420	13,992	35,211
Accounts receivable, net	150,859	137,523
Other current assets	39,235	44,708
Total current assets	208,465	229,651
Property and equipment, net	23,956	25,466
Goodwill	558,978	558,978
Other intangible assets, net	21,058	21,959
Investments in subsidiaries	2,105,159	2,065,819
Other assets	39,316	47,308
Total assets	2,956,932	2,949,181
Liabilities
Intercompany payables	1,064,715	1,027,050
Other current liabilities	79,899	137,710
Total current liabilities	1,144,614	1,164,760
Long-term debt, net	402,717	365,528
Other liabilities	213,072	211,535
Total liabilities	1,760,403	1,741,823
Stockholders' equity	1,196,529	1,207,358
Total liabilities and stockholders' equity	2,956,932	2,949,181
Guarantor Subsidiaries
Assets
Cash and cash equivalents	157	156	163	165
Accounts receivable, net	195,389	163,820
Intercompany receivables	1,012,679	1,029,800
Other current assets	24,973	24,944
Total current assets	1,233,198	1,218,720
Property and equipment, net	13,249	14,118
Goodwill	416,053	416,053
Other intangible assets, net	12,852	13,393
Investments in subsidiaries	507,788	490,634
Other assets	63,396	65,398
Total assets	2,246,536	2,218,316
Liabilities
Other current liabilities	118,884	129,810
Total current liabilities	118,884	129,810
Other liabilities	17,503	16,411
Total liabilities	136,387	146,221
Stockholders' equity	2,110,149	2,072,095
Total liabilities and stockholders' equity	2,246,536	2,218,316
Non-Guarantor Subsidiaries
Assets
Cash and cash equivalents	102,431	168,582	$ 100,296	$ 114,384
Accounts receivable, net	179,932	173,554
Intercompany receivables	52,036
Other current assets	25,789	22,464
Total current assets	360,188	364,600
Property and equipment, net	22,269	22,272
Goodwill	208,596	204,970
Other intangible assets, net	33,223	34,725
Other assets	39,718	35,514
Total assets	663,994	662,081
Liabilities
Intercompany payables		2,750
Other current liabilities	94,545	110,935
Total current liabilities	94,545	113,685
Other liabilities	49,413	46,081
Total liabilities	143,958	159,766
Stockholders' equity	520,036	502,315
Total liabilities and stockholders' equity	663,994	662,081
Eliminations
Assets
Intercompany receivables	(1,064,715)	(1,029,800)
Total current assets	(1,064,715)	(1,029,800)
Other intangible assets, net	(17,238)	(17,957)
Investments in subsidiaries	(2,612,947)	(2,556,453)
Total assets	(3,694,900)	(3,604,210)
Liabilities
Intercompany payables	(1,064,715)	(1,029,800)
Total current liabilities	(1,064,715)	(1,029,800)
Total liabilities	(1,064,715)	(1,029,800)
Stockholders' equity	(2,630,185)	(2,574,410)
Total liabilities and stockholders' equity	$ (3,694,900)	$ (3,604,210)