INVESTMENTS - Gross Unrealized Losses (Narrative) (Details) $ in Thousands	Mar. 31, 2025 USD ($) security	Dec. 31, 2024 USD ($) security
Debt Securities, Available-for-sale [Line Items]
Number of securities in unrealized loss position | security	3,391	3,994
Unrealized loss position	$ 207,764	$ 311,335
Number of securities in a continuous unrealized loss position | security	1,771	2,108
Debt securities fair value	$ 1,806,373	$ 2,253,146
Below Investment Grade or Not Rated
Debt Securities, Available-for-sale [Line Items]
Unrealized loss position	$ 25,000	$ 14,000