DERIVATIVES - Fair Values of Derivatives Reported on Condensed Consolidated Statements of Financial Condition (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Dec. 31, 2024
Derivatives, Fair Value [Line Items]
Derivative assets, fair value	$ 923	$ 4,373
Derivative assets, fair value, total	523	3,787
Derivative assets, notional amount	127,096	360,748
Derivative liabilities, fair value	230,301	289,442
Derivative liabilities, collateral not netted on the condensed consolidated statement of financial condition	(31,978)	(1,132)
Derivative liabilities, fair value, total	190,609	273,148
Derivative liabilities, notional	720,055	531,202
Forward foreign currency exchange rate contracts
Derivatives, Fair Value [Line Items]
Derivative assets, fair value	770	4,248
Derivative assets fair value counterparty and cash collateral netting	(247)	(461)
Derivative assets, notional amount	126,660	359,717
Derivative liabilities, fair value	5,707	1,068
Derivative liabilities, fair value, counterparty and cash collateral netting	(247)	(460)
Derivative liabilities, notional	381,319	167,115
Total return swaps and other
Derivatives, Fair Value [Line Items]
Derivative assets, fair value	153	125
Derivative assets fair value counterparty and cash collateral netting	(153)	(125)
Derivative assets, notional amount	436	1,031
Derivative liabilities, fair value	39,450	17,527
Derivative liabilities, fair value, counterparty and cash collateral netting	(7,467)	(14,702)
Derivative liabilities, notional	177,950	116,239
LFI and other similar deferred compensation arrangements
Derivatives, Fair Value [Line Items]
Derivative assets, fair value	0	0
Derivative assets, notional amount	0	0
Derivative liabilities, fair value	185,144	270,847
Derivative liabilities, notional	160,786	247,848
Net derivatives in "other assets" and "other liabilities"
Derivatives, Fair Value [Line Items]
Derivative assets, net derivatives	523	3,787
Derivative liabilities, net derivatives	$ 222,587	$ 274,280