DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES - Narrative (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2010
Derivative [Line Items]
Interest rate cash flow hedge asset at fair value	$ 102,000									$ 102,000
Interest rate cash flow hedge liability at fair value					$ 381,000						$ 381,000
Interest expense	23,195,000	$ 22,081,000	$ 13,947,000	$ 10,711,000	10,041,000	$ 9,467,000	$ 8,254,000	$ 6,460,000		69,934,000	34,222,000	$ 19,694,000
Mortgages
Derivative [Line Items]
Derivative asset	2,600,000				2,900,000					2,600,000	2,900,000
Derivative liability	1,300,000				67,000					1,300,000	67,000
Interest rate lock commitments | Mortgages
Derivative [Line Items]
Derivative asset, notional amount	$ 81,800,000				86,100,000					$ 81,800,000	86,100,000
Interest Rate Swap
Derivative [Line Items]
Derivative liability, notional amount													$ 37,100,000
Derivative, fixed interest rate	4.11%									4.11%
Interest expense										$ 122,000	484,000	$ 678,000
Forward contracts related to mortgage loans held for sale | Mortgages
Derivative [Line Items]
Derivative, notional amount	$ 163,200,000				$ 158,300,000					$ 163,200,000	$ 158,300,000
London Interbank Offered Rate (LIBOR) | Interest Rate Swap
Derivative [Line Items]
Derivative, basis spread on variable rate	1.63%									1.63%
Scenario, Forecast | Interest Rate Swap
Derivative [Line Items]
Derivative instruments not designated as hedging instruments, gain (loss), net									$ 83,000