PREMISES, EQUIPMENT, AND LEASES - Text (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) lease	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Jan. 01, 2019 USD ($)
Lessee, Lease, Description [Line Items]
Depreciation	$ 12,237	$ 11,228	$ 10,694
Present value of net future minimum lease payments	112,339	117,214
Right-of-use assets	$ 97,859	$ 102,075
Number of real estate leases | lease	36
Rent expense			$ 21,300
Equipment [Member]
Lessee, Lease, Description [Line Items]
Number of equipment leases | lease	24
Accounting Standards Update 2016-02
Lessee, Lease, Description [Line Items]
Present value of net future minimum lease payments				$ 124,100
Right-of-use assets				$ 108,500
Minimum
Lessee, Lease, Description [Line Items]
Initial lease term	5 years
Lease renewal term	5 years
Minimum | Equipment [Member]
Lessee, Lease, Description [Line Items]
Initial lease term	3 years
Maximum
Lessee, Lease, Description [Line Items]
Initial lease term	15 years
Lease renewal term	10 years
Maximum | Equipment [Member]
Lessee, Lease, Description [Line Items]
Initial lease term	5 years