Derivative Financial Instruments (Remaining Contract Maturity Of Fair Value Of OTC Derivative Assets And Liabilities) (Details) (USD $)	Jun. 30, 2014
Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Line Items]
OTC derivative assets having maturity period of 0 to 12 months	$ 226,599,000	[1],[2],[3]
OTC derivative assets having maturity period of 1 to 5 years	130,800,000	[1],[2],[3]
OTC derivative assets having maturity period of greater than 5 years	129,269,000	[1],[2],[3]
OTC derivative assets cross-maturity netting	(84,660,000)	[1],[2],[3],[4]
Total OTC derivative assets, net of cross-maturity netting	402,008,000	[1],[2],[3]
Cross product counterparty netting	(17,810,000)	[1],[2],[3]
Total OTC derivative assets included in Trading assets	384,198,000	[1],[2],[3],[5]
OTC derivative liabilities having maturity period of 0 to 12 months	225,317,000	[3],[6],[7]
OTC derivative liabilities having maturity period of 1 to 5 years	145,975,000	[3],[6],[7]
OTC derivative liabilities having maturity period of greater than 5 years	176,850,000	[3],[6],[7]
OTC derivative liabilities cross-maturity netting	(84,660,000)	[3],[4],[6],[7]
Total OTC derivative liabilities, net of cross-maturity netting	463,482,000	[3],[6],[7]
Cross product counterparty netting	(17,810,000)	[3],[6],[7]
Total OTC derivative liabilities included in Trading liabilities	445,672,000	[3],[6],[7]
Exchange traded derivative assets and other credit agreements	11,600,000
Cash collateral received	143,000,000
Exchange traded derivative liabilities and other credit agreements	22,200,000
Cash collateral pledged	241,600,000
Commodity Swaps, Options And Forwards [Member]
Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Line Items]
OTC derivative assets having maturity period of 0 to 12 months	52,226,000	[1],[2],[3]
OTC derivative assets having maturity period of 1 to 5 years	1,435,000	[1],[2],[3]
Total OTC derivative assets, net of cross-maturity netting	53,661,000	[1],[2],[3]
OTC derivative liabilities having maturity period of 0 to 12 months	78,158,000	[3],[6],[7]
OTC derivative liabilities having maturity period of 1 to 5 years	9,117,000	[3],[6],[7]
Total OTC derivative liabilities, net of cross-maturity netting	87,275,000	[3],[6],[7]
Credit Default Swaps [Member]
Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Line Items]
OTC derivative liabilities having maturity period of 0 to 12 months	51,000	[3],[6],[7]
OTC derivative liabilities having maturity period of 1 to 5 years	8,744,000	[3],[6],[7]
OTC derivative liabilities having maturity period of greater than 5 years	898,000	[3],[6],[7]
Total OTC derivative liabilities, net of cross-maturity netting	9,693,000	[3],[6],[7]
Equity Swaps And Options [Member]
Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Line Items]
OTC derivative assets having maturity period of 0 to 12 months	1,297,000	[1],[2],[3]
Total OTC derivative assets, net of cross-maturity netting	1,297,000	[1],[2],[3]
OTC derivative liabilities having maturity period of greater than 5 years	9,300,000	[3],[6],[7]
Total OTC derivative liabilities, net of cross-maturity netting	9,300,000	[3],[6],[7]
Total Return Swaps [Member]
Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Line Items]
OTC derivative assets having maturity period of 0 to 12 months	6,559,000	[1],[2],[3]
Total OTC derivative assets, net of cross-maturity netting	6,559,000	[1],[2],[3]
OTC derivative liabilities having maturity period of 0 to 12 months	2,200,000	[3],[6],[7]
Total OTC derivative liabilities, net of cross-maturity netting	2,200,000	[3],[6],[7]
Foreign Currency Forwards, Swaps And Options [Member]
Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Line Items]
OTC derivative assets having maturity period of 0 to 12 months	85,715,000	[1],[2],[3]
OTC derivative assets having maturity period of 1 to 5 years	15,283,000	[1],[2],[3]
OTC derivative assets having maturity period of greater than 5 years	51,000	[1],[2],[3]
OTC derivative assets cross-maturity netting	(14,167,000)	[1],[2],[3],[4]
Total OTC derivative assets, net of cross-maturity netting	86,882,000	[1],[2],[3]
OTC derivative liabilities having maturity period of 0 to 12 months	88,516,000	[3],[6],[7]
OTC derivative liabilities having maturity period of 1 to 5 years	16,380,000	[3],[6],[7]
OTC derivative liabilities cross-maturity netting	(14,167,000)	[3],[4],[6],[7]
Total OTC derivative liabilities, net of cross-maturity netting	90,729,000	[3],[6],[7]
Interest Rate Swaps, Options And Forwards [Member]
Remaining Contract Maturity Of Fair Value Of Over Counter Derivative Assets And Liabilities [Line Items]
OTC derivative assets having maturity period of 0 to 12 months	80,802,000	[1],[2],[3]
OTC derivative assets having maturity period of 1 to 5 years	114,082,000	[1],[2],[3]
OTC derivative assets having maturity period of greater than 5 years	129,218,000	[1],[2],[3]
OTC derivative assets cross-maturity netting	(70,493,000)	[1],[2],[3],[4]
Total OTC derivative assets, net of cross-maturity netting	253,609,000	[1],[2],[3]
OTC derivative liabilities having maturity period of 0 to 12 months	56,392,000	[3],[6],[7]
OTC derivative liabilities having maturity period of 1 to 5 years	111,734,000	[3],[6],[7]
OTC derivative liabilities having maturity period of greater than 5 years	166,652,000	[3],[6],[7]
OTC derivative liabilities cross-maturity netting	(70,493,000)	[3],[4],[6],[7]
Total OTC derivative liabilities, net of cross-maturity netting	$ 264,285,000	[3],[6],[7]

[1] At June 30, 2014, we held exchange traded derivative assets and other credit agreements with a fair value of $11.6 million, which are not included in this table.

[2] OTC derivative assets in the table above are gross of collateral received. OTC derivative assets are recorded net of collateral received in the Consolidated Statements of Financial Condition. At June 30, 2014, cash collateral received was $143.0 million.

[3] Derivative fair values include counterparty netting within product category.

[4] Amounts represent the netting of receivable balances with payable balances for the same counterparty within product category across maturity categories.

[5] We utilize internal credit ratings determined by Jefferies Risk Management. Credit ratings determined by Risk Management use methodologies that produce ratings generally consistent with those produced by external rating agencies.

[6] At June 30, 2014, we held exchange traded derivative liabilities and other credit agreements with a fair value of $22.2 million, which are not included in this table.

[7] OTC derivative liabilities in the table above are gross of collateral pledged. OTC derivative liabilities are recorded net of collateral pledged in the Consolidated Statements of Financial Condition. At June 30, 2014, cash collateral pledged was $241.6 million.