INVESTMENT AND MORTGAGE-BACKED SECURITIES, Major Categories of Securities Owned (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Securities, available-for-sale [Abstract]
Amortized Cost	$ 540,812		$ 544,234
Gross Unrealized Gains	18,001		7,403
Gross Unrealized Losses	(988)		(642)
Fair Value	557,825		550,995
Securities pledged as collateral	40,526		27,884
Sales of Available-for-sale Securities [Abstract]
Proceeds	4,199	$ 15,499
Proceeds [Abstract]
Marketable equity securities	137	137
Net (loss) gain on securities	(472)	268
Marketable Equity Securities [Member]
Proceeds [Abstract]
Marketable equity securities	137	137
Net (loss) gain on securities	(472)	268
Agency Notes [Member]
Securities, available-for-sale [Abstract]
Amortized Cost	10,000		20,000
Gross Unrealized Gains	36		0
Gross Unrealized Losses	0		(65)
Fair Value	$ 10,036		19,935
Investment and Mortgage-Backed Securities [Abstract]
Securities weighted average term to maturity	6 years 4 months 24 days
Corporate Securities [Member]
Securities, available-for-sale [Abstract]
Amortized Cost	$ 47,111		28,086
Gross Unrealized Gains	465		510
Gross Unrealized Losses	(544)		0
Fair Value	$ 47,032		28,596
Investment and Mortgage-Backed Securities [Abstract]
Securities weighted average term to maturity	5 years 3 months 18 days
Pass-through MBS Issued by GSEs [Member]
Securities, available-for-sale [Abstract]
Amortized Cost	$ 227,805		241,695
Gross Unrealized Gains	10,829		5,788
Gross Unrealized Losses	0		0
Fair Value	$ 238,634		247,483
Investment and Mortgage-Backed Securities [Abstract]
Securities weighted average term to maturity	17 years
Sales of Available-for-sale Securities [Abstract]
Proceeds	$ 0	6,117
Gross gains	0	0
Tax expense on gain	0	0
Gross losses	0	174
Tax benefit on loss	0	56
Agency CMOs [Member]
Securities, available-for-sale [Abstract]
Amortized Cost	255,896		254,453
Gross Unrealized Gains	6,671		1,105
Gross Unrealized Losses	(444)		(577)
Fair Value	$ 262,123		$ 254,981
Investment and Mortgage-Backed Securities [Abstract]
Securities weighted average term to maturity	17 years
Sales of Available-for-sale Securities [Abstract]
Proceeds	$ 4,199	9,382
Gross gains	8	98
Tax expense on gain	3	31
Gross losses	0	0
Tax benefit on loss	$ 0	$ 0

Refers to the amount of income tax benefit related to loss on sale of mortgage backed securities.

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Refers to the amount of income tax expenses related to gain on sale of mortgage backed securities.

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The weighted average term to maturity.

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Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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

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

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Amount of realized gain on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of realized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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

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Amount of realized gain (loss) from sale of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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The cash inflow associated with the aggregate amount received by the entity through sale or maturity of marketable securities (held-to-maturity or available-for-sale) during the period.

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Amount of cash inflow from sale of investment in mortgage-backed security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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