INVESTMENTS - Additional Information (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Dec. 31, 2019
Gain (Loss) on Securities [Line Items]
Proceeds from Sale of Debt Securities, Available-for-sale	$ 11,400	$ 115,600	$ 41,300	$ 115,600
Available-for-sale Securities, Gross Realized Gains	100	700	100	700
Available-for-sale Securities, Gross Realized Losses	$ 100	700	$ 100	$ 700
Debt Securities, Held-to-maturity, Transfer, Amount		268,700
Realized gain (loss) on debt securities transferred from HTM to AFS		$ 200
NumberOfSecuritiesInSecurityPortfolio	1,290		1,290		1,273
NumberOfSecuritiesInUnrealizedLossPosition	133		133		140
Debt Securities, Held-to-maturity, Nonaccrual	$ 0		$ 0