INVESTMENTS - Additional Information (Details) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Dec. 31, 2018
Gain (Loss) on Securities [Line Items]
Realized gain (loss) on debt securities transferred from HTM to AFS		$ 200
NumberOfSecuritiesInSecurityPortfolio	1,347			1,347		1,417
NumberOfSecuritiesInUnrealizedLossPosition	177			177		504
Proceeds from Sale of Debt Securities, Available-for-sale	$ 115,640		$ 216,197	$ 115,600	$ 216,200
Available-for-sale Securities, Gross Realized Gains	684		0	700
Available-for-sale Securities, Gross Realized Losses	$ 720		30	$ 700
Debt Securities, Held-to-maturity, Transfer, Amount		$ 268,700	$ 367,900