SECURITIES (Securities Debt Maturities) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Amortized Cost
Maturing in one year or less	$ 0
Maturing after one year through five years	0
Maturing after five years through ten years	0
Maturing after ten years through twenty years	27,203
Maturing after twenty years	0
Total with Maturity Date	27,203
Trading Securities, Cost	27,203	$ 27,246
Fair Value
Maturing in one year or less	0
Maturing after one year through five years	0
Maturing after five years through ten years	0
Maturing after ten years through twenty years	25,896
Maturing after twenty years	0
Total with Maturity Date	25,896
Trading Securities, Fair Value	25,896	22,318
Amortized Cost
Maturing in one year or less	10,680
Maturing after one year through five years	84,333
Maturing after five years through ten years	383,987
Maturing after ten years through twenty years	210,917
Maturing after twenty years	958,504
Total with Maturity Date	1,648,421
Available-for-sale Securities, Amortized Cost	1,648,421	926,112
Fair Value
Maturing in one year or less	10,661
Maturing after one year through five years	84,140
Maturing after five years through ten years	381,628
Maturing after ten years through twenty years	210,883
Maturing after twenty years	948,911
Total with Maturity Date	1,636,223
Fair Value	1,636,223	919,485
Amortized Cost
Maturing in one year or less	2,885
Maturing after one year through five years	60,124
Maturing after five years through ten years	62,942
Maturing after ten years through twenty years	70,968
Maturing after twenty years	37,301
Debt Securities, Held-to-maturity	234,220	260,271
Fair Value
Maturing in one year or less	2,875
Maturing after one year through five years	59,591
Maturing after five years through ten years	63,352
Maturing after ten years through twenty years	71,378
Maturing after twenty years	35,341
Debt Securities, Held-to-maturity, Fair Value	$ 232,537	$ 262,188