Schedule I (PARENT COMPANY ONLY) - CONDENSED STATEMENTS OF CASH FLOWS (Details) - USD ($) $ in Thousands	12 Months Ended
	Nov. 30, 2019	Nov. 30, 2018	Nov. 30, 2017
Cash flows from operating activities:
Net earnings	$ 246,029	$ 158,761	$ 357,498
Adjustments to reconcile net earnings to net cash provided by (used in) operating activities:
Amortization	40,942	15,250	1,977
(Income) loss on loans to and investments in related parties	(85,169)	(73,662)	(109,395)
Distributions received on investments in related parties	144,320	62,949	21,038
Other adjustments	61,915	(127,698)	44,043
Net change in assets and liabilities:
Financial instruments owned	35,908	(1,194,791)	(119,087)
Other assets	(41,844)	31,699	8,435
Financial instruments sold, not yet purchased	1,051,600	311,998	(279,282)
Accrued expenses and other liabilities	(126,684)	(224,157)	524,304
Net cash provided by (used in) operating activities	(1,220,149)	126,064	539,946
Cash flows from investing activities:
Cash received from contingent consideration	0	0	1,342
Net cash provided by (used in) investing activities	(124,370)	(121,629)	9,136
Cash flows from financing activities:
Proceeds from short-term borrowings	1,732,232	1,083,416	274,230
Payments on short-term borrowings	(1,597,773)	(1,137,599)	(369,992)
Proceeds from issuance of long-term debt, net of issuance costs	1,239,891	1,367,243	1,116,798
Repayment of long-term debt	(823,875)	(1,035,700)	(186,444)
Distributions to Jefferies Financial Group Inc.	(311,131)	(248,684)	0
Net cash provided by financing activities	1,856,267	190,932	795,474
Net increase in cash, cash equivalents and restricted cash	510,685	176,251	1,356,263
Cash, cash equivalents and restricted cash at beginning of period	5,819,027	5,642,776	4,286,513
Cash, cash equivalents and restricted cash at end of period	6,329,712	5,819,027	5,642,776
Cash paid during the period for:
Interest	1,480,559	1,287,162	1,025,576
Income taxes, net	84,119	196,553	8,910
Parent Company
Cash flows from operating activities:
Net earnings	246,029	158,761	357,498
Adjustments to reconcile net earnings to net cash provided by (used in) operating activities:
Amortization	(38,812)	(53,296)	(61,634)
Undistributed earnings of subsidiaries	(242,558)	(200,275)	(304,520)
(Income) loss on loans to and investments in related parties	(21,946)	(98,223)	(90,724)
Distributions received on investments in related parties	75,000	40,000	0
Other adjustments	60,106	(116,307)	39,513
Net change in assets and liabilities:
Financial instruments owned	26,755	(25,604)	90,399
Other assets	154,940	119,293	(29,031)
Financial instruments sold, not yet purchased	1,510	(17,264)	10,776
Accrued expenses and other liabilities	(51,821)	(200,970)	324,446
Net cash provided by (used in) operating activities	209,203	(393,885)	336,723
Cash flows from investing activities:
Investments in, advances to and subordinated notes receivable from subsidiaries	(1,035,619)	(473,436)	(415,100)
Loans to and investments in related parties	0	0	(73,915)
Cash received from contingent consideration	0	0	1,342
Net cash provided by (used in) investing activities	(1,035,619)	(473,436)	(487,673)
Cash flows from financing activities:
Proceeds from short-term borrowings	20,236	70,482	55,652
Payments on short-term borrowings	(55,773)	(140,664)	(32,326)
Proceeds from issuance of long-term debt, net of issuance costs	1,184,891	1,183,954	1,116,798
Repayment of long-term debt	(823,875)	(1,035,700)	(186,444)
Distributions to Jefferies Financial Group Inc.	(311,131)	(248,684)	0
Net cash provided by financing activities	14,348	(170,612)	953,680
Net increase in cash, cash equivalents and restricted cash	(812,068)	(1,037,933)	802,730
Cash, cash equivalents and restricted cash at beginning of period	979,420	2,017,353	1,214,623
Cash, cash equivalents and restricted cash at end of period	167,352	979,420	2,017,353
Cash paid during the period for:
Interest	291,298	385,410	332,135
Income taxes, net	$ 73,151	$ 186,236	$ 2,494