FAIR VALUE - Additional Information (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Capitalization Rates Utilized To Determine Fair Value Of Underlying Collateral Averaged Percentage	[1]	7.80%
Loans and Leases Receivable, Allowance		$ 27,122	$ 23,400	$ 19,128	$ 17,007
Loans Receivable [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3		400
Other Real Estate Owned And Other Reductions		600
Other Real Estate Owned And Principal Reductions		500
Other Real Estate Owned [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3		1,700
Other Real Estate Revenue		5,000
Other real estate owned and other reductions classified as level three transfers in		1,200
Loans Receivable, Fair Value Disclosure		4,200	4,100
Loans and Leases Receivable, Allowance		2,400	$ 400
Other Real Estate, Disposals		$ 5,300

[1] See Note D for further detail of recurring fair value basis of individual investment categories.