INVESTMENTS (Schedule of Amortized Cost and Estimated Fair Values of Debt Securities by Contractual Maturity) (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Available-for-sale, Amortized Cost
Due in one year or less	$ 0
Due after one year through five years	10,833
Due after five years through ten years	16,274
Due after ten years	0
Subtotal	27,107
Mortgage-related securities	658,156
Available-for-sale securities, book value	685,263	$ 702,937
Available-for-sale, Fair Value
Due in one year or less	0
Due after one year through five years	9,993
Due after five years through ten years	14,780
Due after ten years	0
Subtotal	24,773
Mortgage-related securities	576,803
Fair value, total	$ 601,576	$ 625,808