Related Party Transactions - Related Party Transactions (Details) - USD ($) $ in Thousands	3 Months Ended
	Feb. 28, 2025	Feb. 29, 2024	Nov. 30, 2024
Assets
Cash and cash equivalents	$ 11,176,343		$ 12,153,414
Cash and securities segregated and on deposit for regulatory purposes or deposited with clearing and depository organizations	1,665,894		1,132,612
Financial instruments owned, at fair value	26,087,291		24,138,274
Securities borrowed	8,402,198		7,213,421
Securities purchased under agreements to resell	8,125,231		6,179,653
Receivables:
Brokers, dealers and clearing organizations	3,534,080		2,666,591
Fees, interest and other	707,151		663,536
Other assets	3,294,571		3,072,302
Total assets	70,218,891		64,360,309
Liabilities
Financial instruments sold, not yet purchased, at fair value	13,997,227		11,007,328
Securities loaned	2,501,643		2,540,861
Securities sold under agreements to repurchase	13,664,290		12,337,935
Payables:
Brokers, dealers and clearing organizations	4,221,702		3,686,367
Accrued expenses and other liabilities	2,301,325		3,510,831
Long-term debt	14,785,553		13,530,565
Total liabilities	59,950,046		54,134,916
Revenues
Revenues	2,472,864	$ 2,551,942
Interest expense	879,845	813,739
Net revenues	1,593,019	1,738,203
Non-interest expenses
Business development	72,291	57,651
Other expenses	86,558	83,903
Total non-interest expenses	1,441,954	1,517,961
Principal transactions
Revenues
Revenues	407,230	640,736
Commissions and other fees
Revenues
Revenues	288,300	245,543
Interest
Revenues
Revenues	845,171	$ 819,489
Sumitomo Mitsui Banking Corporation Agreement | Related Party
Assets
Cash and cash equivalents	400,011		542,212
Cash and securities segregated and on deposit for regulatory purposes or deposited with clearing and depository organizations	28,588		0
Financial instruments owned, at fair value	27,747		1,539
Securities borrowed	7,265		20,403
Securities purchased under agreements to resell	355,718		381,568
Receivables:
Brokers, dealers and clearing organizations	1,776		3,012
Fees, interest and other	5,740		7,851
Other assets	131		175
Total assets	826,976		956,760
Liabilities
Financial instruments sold, not yet purchased, at fair value	11,927		1,830
Securities loaned	797		187
Securities sold under agreements to repurchase	562,411		631,390
Payables:
Brokers, dealers and clearing organizations	7,403		18,701
Accrued expenses and other liabilities	8,029		6,767
Long-term debt	350,000		0
Total liabilities	940,567		$ 658,875
Revenues
Revenues	7,923
Interest expense	10,871
Net revenues	(2,948)
Non-interest expenses
Business development	4,688
Other expenses	4
Total non-interest expenses	4,692
Sumitomo Mitsui Banking Corporation Agreement | Related Party | Investment banking
Revenues
Revenues	3,849
Sumitomo Mitsui Banking Corporation Agreement | Related Party | Principal transactions
Revenues
Revenues	(4,192)
Sumitomo Mitsui Banking Corporation Agreement | Related Party | Commissions and other fees
Revenues
Revenues	649
Sumitomo Mitsui Banking Corporation Agreement | Related Party | Interest
Revenues
Revenues	$ 7,617