LOAN PORTFOLIO - Commercial Credit Exposure - Credit RiskProfile Based on Creditworthiness Category (Parenthetical) (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable Held For Sale Net	$ 43,186	$ 32,980
Construction Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable Held For Sale Net	3,015	8,290
Commercial Portfolio Segment [Member] | Commercial And Industrial Sector [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable Held For Sale Net	1,725	0
Nonperforming Financial Instruments [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable Held For Sale Net	16,100	8,300
Nonperforming Financial Instruments [Member] | Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable Held For Sale Net	11,400
Nonperforming Financial Instruments [Member] | Commercial Portfolio Segment [Member] | Commercial And Industrial Sector [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable Held For Sale Net	1,700
Nonperforming Financial Instruments [Member] | Commercial Portfolio Segment [Member] | Construction Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable Held For Sale Net	$ 3,000
Nonperforming Financial Instruments [Member] | Commercial Portfolio Segment [Member] | Construction Loans [Member] | Land [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable Held For Sale Net		$ 8,300