Supplemental Condensed Consolidating Guarantor and Non-Guarantor Financial Information Condensed Consolidating Statement Of Cash Flows (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Operating activities
Net cash provided by (used in) operating activities	$ (82,200)	$ 40,633
Investing activities
Payments for acquisition of businesses, net of cash received		(56)
Purchases of property and equipment	(13,127)	(11,983)
Other	72	96
Net cash used in investing activities	(13,055)	(11,943)
Financing activities
Borrowings under revolving line of credit, net	115,000
Deposits	3,262	2,557
Purchase and retirement of common stock	(102,513)	(2,903)
Net issuance of common stock under equity compensation plans	(500)	9,353
Other	(79)	(154)
Net cash provided by financing activities	15,170	8,853
Effect of exchange rate changes on cash and cash equivalents	2,438	(4,638)
Net increase (decrease) in cash and cash equivalents	(77,647)	32,905
Cash and cash equivalents, beginning of period	216,158	149,760
Cash and cash equivalents, end of period	138,511	182,665
FTI Consulting
Operating activities
Net cash provided by (used in) operating activities	(56,917)	(3,975)
Investing activities
Purchases of property and equipment	(5,440)	(1,533)
Other	72	96
Net cash used in investing activities	(5,368)	(1,437)
Financing activities
Borrowings under revolving line of credit, net	115,000
Purchase and retirement of common stock	(102,513)	(2,903)
Net issuance of common stock under equity compensation plans	(500)	9,353
Other	(79)	418
Intercompany transfers	18,070	36,342
Net cash provided by financing activities	29,978	43,210
Net increase (decrease) in cash and cash equivalents	(32,307)	37,798
Cash and cash equivalents, beginning of period	47,420	35,211
Cash and cash equivalents, end of period	15,113	73,009
Guarantor Subsidiaries
Operating activities
Net cash provided by (used in) operating activities	1,386	42,564
Investing activities
Purchases of property and equipment	(4,655)	(7,821)
Net cash used in investing activities	(4,655)	(7,821)
Financing activities
Other		(572)
Intercompany transfers	3,271	(34,173)
Net cash provided by financing activities	3,271	(34,745)
Net increase (decrease) in cash and cash equivalents	2	(2)
Cash and cash equivalents, beginning of period	156	165
Cash and cash equivalents, end of period	158	163
Non-Guarantor Subsidiaries
Operating activities
Net cash provided by (used in) operating activities	(26,669)	2,044
Investing activities
Payments for acquisition of businesses, net of cash received		(56)
Purchases of property and equipment	(3,032)	(2,629)
Net cash used in investing activities	(3,032)	(2,685)
Financing activities
Deposits	3,262	2,557
Intercompany transfers	(21,341)	(2,169)
Net cash provided by financing activities	(18,079)	388
Effect of exchange rate changes on cash and cash equivalents	2,438	(4,638)
Net increase (decrease) in cash and cash equivalents	(45,342)	(4,891)
Cash and cash equivalents, beginning of period	168,582	114,384
Cash and cash equivalents, end of period	$ 123,240	$ 109,493