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Amount for accounts payable to related parties. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Amount of receivables arising from transactions with related parties due within one year or the normal operating cycle, if longer.

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The aggregate fair value as of the balance sheet date of financial instruments and other positions owned by the entity including: (1) mortgages, mortgage-backed and asset backed securities; (2) US government and agency obligations; (3) state and municipal government obligations; (4) other sovereign government debt; (5) corporate obligations; (6) corporate equities; (7) principal investments; (8) derivative contracts; and (9) physical commodities. Includes both pledged and unpledged holdings.

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The net gain (loss) realized from the sale, exchange, redemption, or retirement of securities, not separately or otherwise categorized as trading, available-for-sale, or held-to-maturity.

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For an unclassified balance sheet, reflects the carrying amount of unpaid loan amounts due from related parties at the balance sheet date.

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The minimum amount the entity agreed to spend under the long-term purchase commitment.

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The distributions of earnings to an entity that is affiliated with the reporting entity by means of direct or indirect ownership.

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The cash inflow from an entity that is affiliated with the entity by means of direct or indirect ownership.

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The cash inflow associated with the sale of debt and equity securities classified as available-for-sale securities.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of revenue, fees and commissions earned from transactions between (a) a parent company and its subsidiaries; (b) subsidiaries of a common parent; (c) an entity and trusts for the benefit of employees, for example, but not limited to, pension and profit-sharing trusts that are managed by or under the trusteeship of the entity's management; (d) an entity and its principal, owners, management, or members of their immediate families; and (e) affiliates.

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Related Party Transactions - Additional Information (Detail) - USD ($)		1 Months Ended			3 Months Ended		6 Months Ended		12 Months Ended
	Feb. 24, 2017	Apr. 30, 2017	Dec. 31, 2016	Mar. 31, 2016	May 31, 2017	May 31, 2016	May 31, 2017	May 31, 2016	Nov. 30, 2016
Related Party Transaction [Line Items]
Purchase commitments from Berkadia Commercial Mortgage, LLC							$ 797,400,000		$ 817,000,000
Loans outstanding to certain employees					$ 47,000,000		47,000,000		38,400,000
Financial instruments, owned, at fair value					13,881,283,000		13,881,283,000		13,809,512,000
Equity Method Investee [Member] \| Equity Investments in Jefferies Capital Partners Related Funds [Member]
Related Party Transaction [Line Items]
Equity investments loans in related funds					28,000,000		28,000,000		37,700,000
Affiliated Entity [Member] \| Investment Banking and Advisory [Member]
Related Party Transaction [Line Items]
Revenue from related parties						$ 1,800,000		$ 1,800,000
Affiliated Entity [Member] \| Asset Management Income [Member]
Related Party Transaction [Line Items]
Revenue from related parties						29,000		100,000
Leucadia [Member] \| Other Assets [Member]
Related Party Transaction [Line Items]
Tax receivable					33,400,000		33,400,000		80,100,000
Leucadia [Member] \| Affiliated Entity [Member]
Related Party Transaction [Line Items]
Revenue from related parties					6,800,000	6,900,000	12,900,000	14,500,000
Due from related party					2,200,000		2,200,000		2,800,000
Due to related party					4,500,000		4,500,000		1,900,000
Proceeds from sale of securities	$ 25,600,000	$ 21,900,000
Gain (loss) on sale of securities	$ 0
Hedge Fund Managed by Subsidiary of Leucadia [Member] \| Affiliated Entity [Member]
Related Party Transaction [Line Items]
Capital contribution amount				$ 114,000,000
Capital redemption			$ 17,000,000
Net gain on investment in hedge fund					1,400,000	$ 900,000	3,200,000	$ 900,000
Corporate debt securities [Member] \| Leucadia [Member] \| Affiliated Entity [Member]
Related Party Transaction [Line Items]
Financial instruments, owned, at fair value					2,600,000		2,600,000		1,000,000
Director [Member] \| Affiliated Entity [Member]
Related Party Transaction [Line Items]
Investment in related party					$ 5,000,000		$ 5,000,000		$ 5,000,000