SECURITIES (Securities available for sale debt maturities) (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Amortized Cost
Due in 1 year or less	$ 1,328
Due in 1 to 5 years	10,563
Due in 5 to 10 years	142,958
Due after 10 years	1,751,868
Total debt securities	1,906,717
Mortgage and asset-backed securities	5,484,637
Equity securities with a readily determinable fair value	20,531	$ 20,788
Total investment securities	7,411,885
Estimated Fair Value
Due in 1 year or less	1,333
Due in 1 to 5 years	10,440
Due in 5 to 10 years	132,583
Due after 10 years	1,588,319
Total debt securities	1,732,675
Mortgage and asset-backed securities	5,272,037
Equity securities with a readily determinable fair value	20,531
Total investment securities	$ 7,025,243

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in sixth through tenth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27198-111563