FAIR VALUE MEASUREMENTS - Schedule of financial assets and financial liabilities measured at fair value on a recurring basis (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Financial assets and financial liabilities measured at fair value
Fair Value	$ 2,087,571	$ 2,461,393
Equity securities	9,812	11,535
U.S. Treasury securities
Financial assets and financial liabilities measured at fair value
Fair Value	15,946	114,061
Obligations of U.S. government corporations and agencies
Financial assets and financial liabilities measured at fair value
Fair Value	5,832	19,779
Obligations of states and political subdivisions
Financial assets and financial liabilities measured at fair value
Fair Value	172,845	257,512
Asset-backed securities
Financial assets and financial liabilities measured at fair value
Fair Value	468,223	469,875
Commercial mortgage-backed securities
Financial assets and financial liabilities measured at fair value
Fair Value	103,509	108,394
Residential mortgage-backed securities
Financial assets and financial liabilities measured at fair value
Fair Value	1,111,312	1,243,256
Corporate debt securities
Financial assets and financial liabilities measured at fair value
Fair Value	209,904	248,516
Fair Value, Recurring \| Derivative assets
Financial assets and financial liabilities measured at fair value
Derivative assets	30,008	42,612
Fair Value, Recurring \| Derivative liabilities
Financial assets and financial liabilities measured at fair value
Derivative liabilities	54,132	72,462
Fair Value, Recurring \| U.S. Treasury securities
Financial assets and financial liabilities measured at fair value
Fair Value	15,946	114,061
Fair Value, Recurring \| Obligations of U.S. government corporations and agencies
Financial assets and financial liabilities measured at fair value
Fair Value	5,832	19,779
Fair Value, Recurring \| Obligations of states and political subdivisions
Financial assets and financial liabilities measured at fair value
Fair Value	172,845	257,512
Fair Value, Recurring \| Asset-backed securities
Financial assets and financial liabilities measured at fair value
Fair Value	468,223	469,875
Fair Value, Recurring \| Commercial mortgage-backed securities
Financial assets and financial liabilities measured at fair value
Fair Value	103,509	108,394
Fair Value, Recurring \| Residential mortgage-backed securities
Financial assets and financial liabilities measured at fair value
Fair Value	1,111,312	1,243,256
Fair Value, Recurring \| Corporate debt securities
Financial assets and financial liabilities measured at fair value
Fair Value	209,904	248,516
Fair Value, Recurring \| Equity securities
Financial assets and financial liabilities measured at fair value
Equity securities	9,812	11,535
Fair Value, Recurring \| Level 1 Inputs \| Derivative assets
Financial assets and financial liabilities measured at fair value
Derivative assets	0	0
Fair Value, Recurring \| Level 1 Inputs \| Derivative liabilities
Financial assets and financial liabilities measured at fair value
Derivative liabilities	0	0
Fair Value, Recurring \| Level 1 Inputs \| U.S. Treasury securities
Financial assets and financial liabilities measured at fair value
Fair Value	0	0
Fair Value, Recurring \| Level 1 Inputs \| Obligations of U.S. government corporations and agencies
Financial assets and financial liabilities measured at fair value
Fair Value	0	0
Fair Value, Recurring \| Level 1 Inputs \| Obligations of states and political subdivisions
Financial assets and financial liabilities measured at fair value
Fair Value	0	0
Fair Value, Recurring \| Level 1 Inputs \| Asset-backed securities
Financial assets and financial liabilities measured at fair value
Fair Value	0	0
Fair Value, Recurring \| Level 1 Inputs \| Commercial mortgage-backed securities
Financial assets and financial liabilities measured at fair value
Fair Value	0	0
Fair Value, Recurring \| Level 1 Inputs \| Residential mortgage-backed securities
Financial assets and financial liabilities measured at fair value
Fair Value	0	0
Fair Value, Recurring \| Level 1 Inputs \| Corporate debt securities
Financial assets and financial liabilities measured at fair value
Fair Value	0	0
Fair Value, Recurring \| Level 1 Inputs \| Equity securities
Financial assets and financial liabilities measured at fair value
Equity securities	448	0
Fair Value, Recurring \| Level 2 Inputs \| Derivative assets
Financial assets and financial liabilities measured at fair value
Derivative assets	29,993	42,607
Fair Value, Recurring \| Level 2 Inputs \| Derivative liabilities
Financial assets and financial liabilities measured at fair value
Derivative liabilities	54,132	72,462
Fair Value, Recurring \| Level 2 Inputs \| U.S. Treasury securities
Financial assets and financial liabilities measured at fair value
Fair Value	15,946	114,061
Fair Value, Recurring \| Level 2 Inputs \| Obligations of U.S. government corporations and agencies
Financial assets and financial liabilities measured at fair value
Fair Value	5,832	19,779
Fair Value, Recurring \| Level 2 Inputs \| Obligations of states and political subdivisions
Financial assets and financial liabilities measured at fair value
Fair Value	172,845	257,512
Fair Value, Recurring \| Level 2 Inputs \| Asset-backed securities
Financial assets and financial liabilities measured at fair value
Fair Value	468,223	469,875
Fair Value, Recurring \| Level 2 Inputs \| Commercial mortgage-backed securities
Financial assets and financial liabilities measured at fair value
Fair Value	103,509	108,394
Fair Value, Recurring \| Level 2 Inputs \| Residential mortgage-backed securities
Financial assets and financial liabilities measured at fair value
Fair Value	1,111,312	1,243,256
Fair Value, Recurring \| Level 2 Inputs \| Corporate debt securities
Financial assets and financial liabilities measured at fair value
Fair Value	209,904	248,516
Fair Value, Recurring \| Level 2 Inputs \| Equity securities
Financial assets and financial liabilities measured at fair value
Equity securities	9,364	11,535
Fair Value, Recurring \| Level 3 Inputs \| Derivative assets
Financial assets and financial liabilities measured at fair value
Derivative assets	15	5
Fair Value, Recurring \| Level 3 Inputs \| Derivative liabilities
Financial assets and financial liabilities measured at fair value
Derivative liabilities	0	0
Fair Value, Recurring \| Level 3 Inputs \| U.S. Treasury securities
Financial assets and financial liabilities measured at fair value
Fair Value	0	0
Fair Value, Recurring \| Level 3 Inputs \| Obligations of U.S. government corporations and agencies
Financial assets and financial liabilities measured at fair value
Fair Value	0	0
Fair Value, Recurring \| Level 3 Inputs \| Obligations of states and political subdivisions
Financial assets and financial liabilities measured at fair value
Fair Value	0	0
Fair Value, Recurring \| Level 3 Inputs \| Asset-backed securities
Financial assets and financial liabilities measured at fair value
Fair Value	0	0
Fair Value, Recurring \| Level 3 Inputs \| Commercial mortgage-backed securities
Financial assets and financial liabilities measured at fair value
Fair Value	0	0
Fair Value, Recurring \| Level 3 Inputs \| Residential mortgage-backed securities
Financial assets and financial liabilities measured at fair value
Fair Value	0	0
Fair Value, Recurring \| Level 3 Inputs \| Corporate debt securities
Financial assets and financial liabilities measured at fair value
Fair Value	0	0
Fair Value, Recurring \| Level 3 Inputs \| Equity securities
Financial assets and financial liabilities measured at fair value
Equity securities	$ 0	$ 0

Amount excluding accrued interest, of 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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