Net Capital Requirements (Detail) $ in Thousands	Aug. 31, 2017 USD ($)
Jefferies
Net Capital Requirements [Line Items]
Net Capital	$ 1,491,122
Excess Net Capital	1,411,625
Jefferies Execution
Net Capital Requirements [Line Items]
Net Capital	7,961
Excess Net Capital	$ 7,711

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