Net Capital Requirements (Details) (USD $) In Thousands	Aug. 31, 2011
Jefferies [Member]
Net capital and excess net capital
Net Capital	$ 762,729
Excess Net Capital	693,313
Jefferies Execution [Member]
Net capital and excess net capital
Net Capital	15,651
Excess Net Capital	15,401
Jefferies High Yield Trading [Member]
Net capital and excess net capital
Net Capital	527,962
Excess Net Capital	527,712
Jefferies Bache Securities, LLC [Member]
Net capital and excess net capital
Net Capital	3,464
Excess Net Capital	3,214
Jefferies Bache, LLC [Member]
Net capital and excess net capital
Net Capital	248,824
Excess Net Capital	$ 41,335