SECURITIES - Summary of Held to Maturity Investment Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Held to maturity:
Amortized Cost	$ 124,231	$ 133,638
Gross Unrealized Gains	3,432	1,731
Gross Unrealized Losses	(10)	(342)
Estimated Fair Value	127,653	135,027
State and municipal obligations
Held to maturity:
Amortized Cost	34,046	41,008
Gross Unrealized Gains	807	809
Estimated Fair Value	34,853	41,817
U.S. GSE residential mortgage-backed securities
Held to maturity:
Amortized Cost	7,737	8,142
Gross Unrealized Gains	141	5
Gross Unrealized Losses		(54)
Estimated Fair Value	7,878	8,093
U.S. GSE residential collateralized mortgage obligations
Held to maturity:
Amortized Cost	38,076	39,936
Gross Unrealized Gains	1,610	624
Gross Unrealized Losses		(62)
Estimated Fair Value	39,686	40,498
U.S. GSE commercial mortgage-backed securities
Held to maturity:
Amortized Cost	17,021	17,215
Gross Unrealized Gains	503	102
Gross Unrealized Losses		(82)
Estimated Fair Value	17,524	17,235
U.S. GSE commercial collateralized mortgage obligations
Held to maturity:
Amortized Cost	27,351	27,337
Gross Unrealized Gains	371	191
Gross Unrealized Losses	(10)	(144)
Estimated Fair Value	$ 27,712	$ 27,384

Amount of investment in debt security measured at amortized cost (held-to-maturity).

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Amount of accumulated unrecognized gain on investment in debt security measured at amortized cost (held-to-maturity).

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Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity).

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Fair value of investment in debt security measured at amortized cost (held-to-maturity).

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