NATURE OF BUSINESS AND SIGNIFICANT ACCOUNTING POLICIES - Narrative (Detail) - USD ($)	1 Months Ended	12 Months Ended
	May 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2019
Nature Of Business And Significant Accounting Policies [Line Items]
Operating lease liability		$ 3,923,000
Restricted cash		6,000,000	$ 6,300,000	$ 5,400,000
Other investments		24,072,000	17,997,000
Material loans criteria for ALLL adequacy calculation		250,000
Goodwill, Impairment Loss		762,000	0
Restricted cash pledged as collateral		$ 1,300,000
Core deposit intangibles
Nature Of Business And Significant Accounting Policies [Line Items]
Amortized period of core deposit intangible		10 years
Customer list intangibles:
Nature Of Business And Significant Accounting Policies [Line Items]
Amortized period of core deposit intangible		12 years
Accounting Standards Update 2016-02
Nature Of Business And Significant Accounting Policies [Line Items]
Operating lease liability						$ 5,000,000
Right-of-use asset						$ 5,000,000
Minimum | Securities sold under agreements to repurchase
Nature Of Business And Significant Accounting Policies [Line Items]
Maturity period of repo agreements		1 day
Maximum | Securities sold under agreements to repurchase
Nature Of Business And Significant Accounting Policies [Line Items]
Maturity period of repo agreements		4 days
United Financial Services, Inc. | United Financial Services Llc
Nature Of Business And Significant Accounting Policies [Line Items]
Percentage of indirect interest					49.80%
Percentage of Indirect Interest Sold	80.00%
Equity Method Investment, Realized Gain (Loss) on Disposal	$ 7,400,000
Equity income recognized in business acquisition		$ 900,000	1,800,000	1,300,000
Payment made for acquisition		3,200,000	2,800,000	$ 2,600,000
Carrying value of bank investment		$ 2,800,000	$ 11,500,000