Net Capital Requirements (Detail) $ in Thousands	Feb. 28, 2017 USD ($)
Jefferies [Member]
Net Capital Requirements [Line Items]
Net Capital	$ 1,359,023
Excess Net Capital	1,277,401
Jefferies Execution [Member]
Net Capital Requirements [Line Items]
Net Capital	9,158
Excess Net Capital	$ 8,908

Net capital is equal to the net worth of the broker dealer, less certain items such as exchange memberships, carrying value of securities not readily marketable, haircuts on marketable securities in proprietary accounts, furniture and equipment and other illiquid assets as defined.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Rule 15c3-1
-Number 240
-Section 15c3-1

Name:	us-gaap_NetCapital
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant