INCOME TAXES - Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Gross deferred tax assets:
Allowance for loan and OREO losses	$ 26,444	$ 21,789
Interest on nonaccrual loans	214	172
Stock compensation	1,324	1,710
Deferred and accrued compensation	13,010	13,096
Lease liabilities	32,068	34,129
PPP loan origination fees	1,692	0
Other	1,618	1,129
Total gross deferred tax assets	76,370	72,025
Gross deferred tax liabilities:
Goodwill and acquired intangible assets	14,579	13,333
Fixed assets	4,979	4,518
Right-of-use assets	30,673	32,454
Prepaid expenses	405	385
Loan servicing fees	545	0
Contingent payments	5,688	6,764
Unrealized gain on investments	12,441	2,949
Other	286	239
Total gross deferred tax liabilities	69,596	60,642
Net deferred tax assets	$ 6,774	$ 11,383