LOAN PORTFOLIO - Selected Information on TDRs Includes Recorded Investment by Loan Class and Modification Type (Parenthetical) (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Financing Receivable Modifications [Line Items]
Loans Receivable Held For Sale Net	$ 33,175	$ 43,186
Commercial Portfolio Segment [Member] | Commercial And Industrial Sector [Member]
Financing Receivable Modifications [Line Items]
Loans Receivable Held For Sale Net	0	1,725
Commercial Portfolio Segment [Member] | Mortgage Receivable [Member]
Financing Receivable Modifications [Line Items]
Loans Receivable Held For Sale Net	7,381	11,371
Nonaccrual [Member]
Financing Receivable Modifications [Line Items]
Loans Receivable Held For Sale Net	7,400	16,100
Nonaccrual [Member] | Commercial Portfolio Segment [Member] | Commercial And Industrial Sector [Member]
Financing Receivable Modifications [Line Items]
Loans Receivable Held For Sale Net		1,700
Nonaccrual [Member] | Commercial Portfolio Segment [Member] | Mortgage Receivable [Member]
Financing Receivable Modifications [Line Items]
Loans Receivable Held For Sale Net	7,400	11,400
TDR [Member] | Nonaccrual [Member] | Commercial Portfolio Segment [Member] | Commercial And Industrial Sector [Member]
Financing Receivable Modifications [Line Items]
Loans Receivable Held For Sale Net		900
TDR [Member] | Nonaccrual [Member] | Commercial Portfolio Segment [Member] | Mortgage Receivable [Member]
Financing Receivable Modifications [Line Items]
Loans Receivable Held For Sale Net	$ 7,400	$ 11,100