SECURITIES (Securities available for sale debt maturities) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Amortized Cost
Due in 1 year or less	$ 29,138
Due in 1 to 5 years	51,367
Due in 5 to 10 years	123,062
Due after 10 years	304,758
Total debt securities	508,325
Mortgage and asset-backed securities	1,889,977
Equity securities with a readily determinable fair value	17,339
Amortized Cost	2,415,641	$ 2,492,620
Estimated Fair Value
Due in 1 year or less	29,100
Due in 1 to 5 years	50,972
Due in 5 to 10 years	123,289
Due after 10 years	308,362
Total debt securities	511,723
Mortgage and asset-backed securities	1,871,398
Equity securities with a readily determinable fair value	17,339
Estimated Fair Value	$ 2,400,460	$ 2,450,709