Variable Interest Entities - Assets and Liabilities of Consolidated VIEs Prior to Consolidation (Details) - USD ($) $ in Thousands	Nov. 30, 2020	Nov. 30, 2019
Variable Interest Entity [Line Items]
Total assets	$ 47,751,997	$ 43,516,115
Total liabilities	41,385,865	37,386,368
Variable interest entity, primary beneficiary | Securitization activity
Variable Interest Entity [Line Items]
Total assets	2,908,900	2,467,300
Total liabilities	2,908,900	2,467,300
Variable interest entity, primary beneficiary | Other
Variable Interest Entity [Line Items]
Total assets	19,400	1,500
Total liabilities	2,900	200
Cash | Variable interest entity, primary beneficiary
Variable Interest Entity [Line Items]
VIE assets, eliminated in consolidation	700
Cash | Variable interest entity, primary beneficiary | Securitization activity
Variable Interest Entity [Line Items]
Total assets	0	0
Cash | Variable interest entity, primary beneficiary | Other
Variable Interest Entity [Line Items]
Total assets	1,200	1,200
Financial instruments owned | Variable interest entity, primary beneficiary | Securitization activity
Variable Interest Entity [Line Items]
Total assets	0	0
Financial instruments owned | Variable interest entity, primary beneficiary | Other
Variable Interest Entity [Line Items]
Total assets	5,200	300
Securities purchased under agreements to resell | Variable interest entity, primary beneficiary | Securitization activity
Variable Interest Entity [Line Items]
Total assets	2,908,900	2,467,300
Securities purchased under agreements to resell | Variable interest entity, primary beneficiary | Other
Variable Interest Entity [Line Items]
Total assets	0	0
Receivable from brokers | Variable interest entity, primary beneficiary | Securitization activity
Variable Interest Entity [Line Items]
Total assets	0	0
Receivable from brokers | Variable interest entity, primary beneficiary | Other
Variable Interest Entity [Line Items]
Total assets	12,900	0
Other assets | Securitization activity
Variable Interest Entity [Line Items]
Total assets		0
Other assets | Other
Variable Interest Entity [Line Items]
Total assets	100
Other assets | Variable interest entity, primary beneficiary | Securitization activity
Variable Interest Entity [Line Items]
Total assets	0
Other assets | Variable interest entity, primary beneficiary | Other
Variable Interest Entity [Line Items]
Total assets		0
Financial instruments sold, not yet purchased | Variable interest entity, primary beneficiary | Securitization activity
Variable Interest Entity [Line Items]
Total liabilities	0	0
Financial instruments sold, not yet purchased | Variable interest entity, primary beneficiary | Other
Variable Interest Entity [Line Items]
Total liabilities	2,500	0
Other secured financings | Variable interest entity, primary beneficiary
Variable Interest Entity [Line Items]
VIE liabilities, eliminated in consolidation	138,200
Other secured financings | Variable interest entity, primary beneficiary | Securitization activity
Variable Interest Entity [Line Items]
Total liabilities	2,907,800	2,465,800
Other secured financings | Variable interest entity, primary beneficiary | Other
Variable Interest Entity [Line Items]
Total liabilities	0	0
Other liabilities | Variable interest entity, primary beneficiary
Variable Interest Entity [Line Items]
VIE liabilities, eliminated in consolidation	300	200
Other liabilities | Variable interest entity, primary beneficiary | Securitization activity
Variable Interest Entity [Line Items]
Total liabilities	1,100	1,500
Other liabilities | Variable interest entity, primary beneficiary | Other
Variable Interest Entity [Line Items]
Total liabilities	$ 400	$ 200