Leucadia Merger and Related Transactions - Additional Information (Detail) (USD $)	1 Months Ended	6 Months Ended		1 Months Ended	6 Months Ended
	Mar. 31, 2013 Leucadia [Member]	May 31, 2013 Leucadia [Member]	Feb. 28, 2013 Leucadia [Member]	Feb. 28, 2013 Jefferies High Yield Holdings, LLC [Member]	May 31, 2013 3.875% Convertible Senior Debentures, due 2029 [Member] Leucadia [Member]	May 31, 2013 3.25% Cumulative Convertible Preferred Shares [Member]	May 31, 2013 3.25% Cumulative Convertible Preferred Shares [Member] Leucadia [Member]	May 31, 2013 Series A-1 Convertible Cumulative Preferred Stock [Member]	May 31, 2013 Series A-1 Convertible Cumulative Preferred Stock [Member] Jefferies Group Inc. [Member]
Loans At Acquisition Date [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%
Debt instrument maturity year					2029
Cost of assets acquired		4,754,101,000
Business acquisition transaction cost		9,000,000	2,100,000
Intangible assets not including good will		283,400,000
Goodwill		1,701,616,000
Third party noncontrolling interests redeemed				347,629,000
Redeemable preferred interests	$ 362,255,000