LEASES - Narrative (Details) $ in Thousands		3 Months Ended	12 Months Ended
	Apr. 01, 2020 USD ($) operating_lease location	Mar. 31, 2020 USD ($) location	Dec. 31, 2020 USD ($) operating_lease	Dec. 31, 2019 USD ($)
Lessee, Lease, Description [Line Items]
Right-of-use asset obtained in exchange for operating lease liability			$ 871	$ 399
Operating lease liabilities			$ 74,982	76,871
Number of operating leases acquired likely to be terminated | operating_lease			7
Operating lease ROU assets			$ 65,215	$ 69,320
Branch Location
Lessee, Lease, Description [Line Items]
Number of operating leases acquired likely to be terminated | operating_lease			6
Office Space
Lessee, Lease, Description [Line Items]
Number of operating leases acquired likely to be terminated | operating_lease			1
Minimum
Lessee, Lease, Description [Line Items]
Renewal term			1 year
Maximum
Lessee, Lease, Description [Line Items]
Renewal term			20 years
Revere acquisition
Lessee, Lease, Description [Line Items]
Right-of-use asset obtained in exchange for operating lease liability	$ 7,400
Number of operating leases | operating_lease	15
Number of locations operating leases | location	12
Operating lease liabilities	$ 8,700
Liabilities arising from contingencies	1,100
Tenant improvements	200
Asset impairment charges	$ 2,300
Acquisition of Rembert Pendleton Jackson
Lessee, Lease, Description [Line Items]
Number of locations acquired | location		2
Right-of-use asset obtained in exchange for operating lease liability		$ 300
Lease operation commence in 2021
Lessee, Lease, Description [Line Items]
Operating lease liabilities			$ 2,100
Liabilities arising from contingencies			500
Tenant improvements			200
Operating lease ROU assets			$ 1,400