SECURITIES - Amortized Cost and Fair Value By Contractual Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Available for sale, Amortized Cost
Within one year	$ 4,226
One to five years	277,389
Five to ten years	150,906
Beyond ten years	5,145
Pass-through MBS issued by GSEs and Agency CMO	913,074
Amortized Cost	1,350,740	$ 1,574,094
Available for sale, Fair Value
Within one year	4,196
One to five years	262,734
Five to ten years	146,993
Beyond ten years	4,814
Pass-through MBS issued by GSEs and Agency CMO	858,299
Total	1,277,036	1,563,711
Held-to-maturity, Amortized Cost
One to five years	10,000
Five to ten years	78,858
Pass-through MBS issued by GSEs and agency CMO	295,064
Total	383,922
Held-to-maturity, Fair Value
One to five years	9,827
Five to ten years	74,006
Pass-through MBS issued by GSEs and agency CMO	274,856
Fair Value	$ 358,689	$ 177,354