SEGMENT REPORTING - Narrative (Detail) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) segment	Sep. 30, 2020 USD ($)
Segment Reporting Information [Line Items]
Number of operating segments | segment			3
Amortization of Intangible Assets	$ 1,635	$ 1,968	$ 4,991	$ 4,566
Community Banking
Segment Reporting Information [Line Items]
Amortization of Intangible Assets	1,200	1,400	3,500	3,200
Insurance
Segment Reporting Information [Line Items]
Amortization of Intangible Assets			0	0
Investment Management
Segment Reporting Information [Line Items]
Amortization of Intangible Assets	500	$ 500	1,400	$ 1,400
Investment Management | West Financial and RPJ
Segment Reporting Information [Line Items]
Assets under management	$ 3,800,000		$ 3,800,000