DEBT SECURITIES - Schedule of Debt Securities in an Unrealized or Unrecognized Loss Position (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Fair Value
Less than 12 months	$ 175,459	$ 13,033
12 months or more	1,547,816	2,049,784
Total	1,723,275	2,062,817
Unrealized Losses
Less than 12 months	(206)	(65)
12 months or more	(246,591)	(247,180)
Total	(246,797)	(247,245)
Fair Value
12 months or more	697,455	730,397
Total	697,455	730,397
Unrecognized Losses
12 months or more	(153,806)	(142,231)
Total	(153,806)	(142,231)
U.S. Treasury securities
Fair Value
Less than 12 months	0	0
12 months or more	497	15,946
Total	497	15,946
Unrealized Losses
Less than 12 months	0	0
12 months or more	(3)	(85)
Total	(3)	(85)
Obligations of U.S. government corporations and agencies
Fair Value
Less than 12 months	0	0
12 months or more	3,686	5,709
Total	3,686	5,709
Unrealized Losses
Less than 12 months	0	0
12 months or more	(11)	(58)
Total	(11)	(58)
Obligations of states and political subdivisions
Fair Value
Less than 12 months	5,465	11,442
12 months or more	135,744	146,797
Total	141,209	158,239
Unrealized Losses
Less than 12 months	(64)	(54)
12 months or more	(18,200)	(17,972)
Total	(18,264)	(18,026)
Asset-backed securities
Fair Value
Less than 12 months	159,674	0
12 months or more	184,078	468,223
Total	343,752	468,223
Unrealized Losses
Less than 12 months	(86)	0
12 months or more	(383)	(1,823)
Total	(469)	(1,823)
Commercial mortgage-backed securities
Fair Value
Less than 12 months	0	0
12 months or more	88,867	103,509
Total	88,867	103,509
Unrealized Losses
Less than 12 months	0	0
12 months or more	(15,741)	(15,535)
Total	(15,741)	(15,535)
Fair Value
12 months or more	345,067	357,526
Total	345,067	357,526
Unrecognized Losses
12 months or more	(77,024)	(71,000)
Total	(77,024)	(71,000)
Residential mortgage-backed securities
Fair Value
Less than 12 months	5,905	141
12 months or more	987,618	1,110,906
Total	993,523	1,111,047
Unrealized Losses
Less than 12 months	(37)	(1)
12 months or more	(201,211)	(195,546)
Total	(201,248)	(195,547)
Fair Value
12 months or more	352,388	372,871
Total	352,388	372,871
Unrecognized Losses
12 months or more	(76,782)	(71,231)
Total	(76,782)	(71,231)
Corporate debt securities
Fair Value
Less than 12 months	4,415	1,450
12 months or more	147,326	198,694
Total	151,741	200,144
Unrealized Losses
Less than 12 months	(19)	(10)
12 months or more	(11,042)	(16,161)
Total	$ (11,061)	$ (16,171)