Investments - Summary of Selected Financial information for Other Asset Management Companies (Details) - USD ($) $ in Thousands	12 Months Ended
	Nov. 30, 2024	Nov. 30, 2023	Nov. 30, 2022	Sep. 30, 2024
Schedule of Equity Method Investments [Line Items]
Total assets	$ 64,360,309	$ 57,905,161
Total liabilities	54,134,916	48,102,620
Total members’ equity	10,224,987	9,802,135	$ 10,295,479
Net increase (decrease) in members’ equity resulting from operations		$ 61,400	$ (4,500)
Hildene Insurance Holdings, LLC
Schedule of Equity Method Investments [Line Items]
Net increase (decrease) in members’ equity resulting from operations	$ 34,100
Hildene Insurance Holdings, LLC
Schedule of Equity Method Investments [Line Items]
Total assets				$ 304,200
Total liabilities				200
Total members’ equity				$ 304,000