Leucadia Merger and Related Transactions - Additional Information (Detail) (USD $)		3 Months Ended			3 Months Ended	6 Months Ended	3 Months Ended	1 Months Ended		9 Months Ended	3 Months Ended
	May 31, 2013	Feb. 28, 2013 Leucadia [Member]	May 31, 2013 Leucadia [Member]	Mar. 31, 2013 Leucadia [Member]	Aug. 31, 2013 Leucadia [Member] Successor [Member]	Aug. 31, 2013 Leucadia [Member] Successor [Member]	Feb. 28, 2013 Leucadia [Member] Predecessor [Member]	Feb. 28, 2013 Jefferies High Yield Holdings, LLC [Member]	Aug. 31, 2013 3.875% Convertible Senior Debentures, due 2029 [Member] Successor [Member]	Aug. 31, 2013 3.875% Convertible Senior Debentures, due 2029 [Member] Leucadia [Member]	Feb. 28, 2013 3.25% Cumulative Convertible Preferred Shares [Member]	Feb. 28, 2013 3.25% Cumulative Convertible Preferred Shares [Member] Leucadia [Member]	Feb. 28, 2013 Series A-1 Convertible Cumulative Preferred Stock [Member]	Feb. 28, 2013 Series A-1 Convertible Cumulative Preferred Stock [Member] Jefferies Group Inc. [Member]
Business Acquisition [Line Items]
Exchange ratio		0.81
Convertible Cumulative Preferred Stock		$ 125,000,000										$ 125,000,000		$ 125,000,000
Convertible Cumulative Preferred Stock, dividend rate		3.25%									3.25%	3.25%	3.25%	3.25%
Debt instrument principal amount										345,000,000
Debt instrument interest rate			3.875%						3.875%	3.875%
Debt instrument maturity year										2029
Cost of assets acquired		4,754,101,000
Business acquisition transaction cost					2,500,000	11,500,000	2,100,000
Intangible assets, not including good will		282,900,000
Goodwill	5,300,000	1,715,986,000
Third party noncontrolling interests redeemed								347,600,000
Redeemable preferred interests				$ 362,300,000