SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2018 USD ($) Employee Bank		Dec. 31, 2017 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of full service banking offices | Bank	20
Number of employees | Employee	251
Unfunded loan commitments	$ 40,000		$ 32,000
Additional income tax expense	557,000	[1]	$ 300,000
Fair value of cost method investments	1,300,000
ASU 2016-01 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Equity securities	1,400,000
Exchange Traded Equity Securities [Member] | ASU 2016-01 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Fair value of cost method investments	$ 1,400,000

[1] The Tax Cuts and Jobs Act, enacted on December 22, 2017, required the revaluation of the Company’s deferred tax assets and liabilities as of December 31, 2017 as a result of the lower corporate tax rates to be realized beginning January 1, 2018. The $0.6 million adjustment to retained earnings for the period ended March 31, 2018 represents a reclassification of the tax effects of the Tax Cuts and Jobs Act.