SECURITIES (Securities Debt Maturities) (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Investments, Debt and Equity Securities [Abstract]
Trading Securities, Amortized Cost, Maturing after ten years through twenty years	$ 27,203
Debt Securities, Trading, Amortized Cost	27,203	$ 27,203
Trading Securities, Fair Value, Maturing in one year or less	0
Trading Securities, Fair Value, Maturing after one year through five years	0
Trading Securities, Fair Value, Maturing after five years through ten years	0
Trading Securities, Fair Value, Maturing after ten years through twenty years	27,354
Trading Securities, Fair Value	27,354	26,981
Available-for-sale Securities, Amortized Cost, Maturing in one year or less	9,100
Available-for-sale Securities, Amortized Cost, Maturing after one year through five years	187,185
Available-for-sale Securities, Amortized Cost, Maturing after five years through ten years	799,161
Available-for-sale Securities, Amortized Cost, Maturing after ten years through twenty years	2,319,767
Debt Securities, Available-for-sale, Amortized Cost, Total	3,315,213	3,653,160
Available-for-sale Securities, Fair Value, Maturing in one year or less	9,126
Available-for-sale Securities, Fair Value, Maturing after one year through five years	187,107
Available-for-sale Securities, Fair Value, Maturing after five years through ten years	771,687
Available-for-sale Securities, Fair Value, Maturing after ten years through twenty years	2,179,627
Debt Securities, Available-for-sale	3,147,547	3,638,993
Held-to-maturity Securities, Amortized Cost, Maturing in one year or less	9,664
Held-to-maturity Securities, Amortized Cost, Maturing after one year through five years	45,900
Held-to-maturity Securities, Amortized Cost, Maturing after five years through ten years	26,908
Held-to-maturity Securities, Amortized Cost, Maturing after ten years through twenty years	933,470
Held-to-maturity Securities, Amortized Cost	1,015,942	521,355
Held-to-maturity Securities, Fair Value, Maturing in one year or less	9,670
Held-to-maturity Securities, Fair Value, Maturing after one year through five years	46,116
Held-to-maturity Securities, Fair Value, Maturing after five years through ten years	27,091
Held-to-maturity Securities, Fair Value, Maturing after ten years through twenty years	885,663
Debt Securities, Held-to-maturity, Fair Value	968,540	$ 541,853
Trading Securities, Amortized Cost, Maturing in one year or less	0
Trading Securities, Amortized Cost, Maturing after one year through five years	0
Trading Securities, Amortized Cost, Maturing after five years through ten years	$ 0