INVESTMENTS - Additional Information (Details) $ in Thousands	3 Months Ended	6 Months Ended
Mar. 31, 2026 USD ($) entity	Mar. 31, 2025 USD ($)	Jun. 30, 2025 USD ($) entity	Dec. 31, 2025 USD ($)
Gain (Loss) on Securities [Line Items]
Proceeds from Sale of Debt Securities, Available-for-sale	$ 195,665	$ 164,535
Debt Securities, Available-for-sale, Realized Gain	4,000	100
Available-for-sale Securities, Gross Realized Losses	0	10,000
Debt Securities, Held-to-maturity, Allowance for Credit Loss	$ 0			$ 0
NumberOfSecuritiesInSecurityPortfolio	874			949
NumberOfSecuritiesInUnrealizedLossPosition	673			533
Debt Securities, Held-to-maturity, Nonaccrual	$ 0			$ 0
Net gain (loss) on investment securities	(1,260)	(9,949)
Debt Securities, Available-for-Sale, Unrealized Loss Position	3,788,755			2,110,835
Debt Securities, Unrealized Gain (Loss)	$ 5,600		$ 9,800
Debt Securities, Available-for-Sale, Realized Gain (Loss), Number \| entity	6		6
Debt Securities, Realized Gain (Loss)	$ 5,000	$ 0
Financial Instrument, Other
Gain (Loss) on Securities [Line Items]
Debt Securities, Available-for-Sale, Unrealized Loss Position	$ 22,500			$ 20,900

Debt Securities, Available-for-Sale, Realized Gain (Loss), Number

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The total number of securities included in the investment securities portfolio.

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The total number of securities included in the investment securities portfolio that include net accumulated unrealized losses.

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Amount of unrealized and realized gain (loss) on investment in debt and equity securities.

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Amount of realized gain on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of realized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position without allowance for credit loss.

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Amount of investment in debt security measured at amortized cost (held-to-maturity) on nonaccrual status.

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