SECURITIES - Available for Sale Investment Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Amortized Cost, Available for sale:
Within one year	$ 61,121
One to five years	44,986
Five to ten years	58,330
Beyond ten years	384,184
Total	548,621	$ 639,463
Estimated Fair Value, Available for sale:
Within one year	61,140
One to five years	44,668
Five to ten years	56,068
Beyond ten years	391,402
Estimated Fair Value	553,278	638,291
U.S. Treasury securities
Amortized Cost, Available for sale:
Total	59,980	50,833
Estimated Fair Value, Available for sale:
Estimated Fair Value	59,999	50,822
U.S. GSE securities
Amortized Cost, Available for sale:
Total		5,000
Estimated Fair Value, Available for sale:
Estimated Fair Value		4,995
State and municipal obligations
Amortized Cost, Available for sale:
Total	37,233	34,303
Estimated Fair Value, Available for sale:
Estimated Fair Value	37,946	34,964
U.S. GSE residential mortgage-backed securities
Amortized Cost, Available for sale:
Total	80,136	84,550
Estimated Fair Value, Available for sale:
Estimated Fair Value	81,654	84,691
U.S. GSE residential collateralized mortgage obligations
Amortized Cost, Available for sale:
Total	200,029	278,149
Estimated Fair Value, Available for sale:
Estimated Fair Value	205,492	277,851
U.S. GSE commercial mortgage-backed securities
Amortized Cost, Available for sale:
Total	16,683	13,656
Estimated Fair Value, Available for sale:
Estimated Fair Value	17,049	13,609
U.S. GSE commercial collateralized mortgage obligations
Amortized Cost, Available for sale:
Total	81,310	102,722
Estimated Fair Value, Available for sale:
Estimated Fair Value	83,380	104,156
Other asset backed securities
Amortized Cost, Available for sale:
Total	24,250	24,250
Estimated Fair Value, Available for sale:
Estimated Fair Value	22,552	23,401
Corporate bonds
Amortized Cost, Available for sale:
Total	49,000	46,000
Estimated Fair Value, Available for sale:
Estimated Fair Value	$ 45,206	$ 43,802

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=118942338&loc=SL82898722-210454

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=118942338&loc=SL82898722-210454

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (b)
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