LOAN PORTFOLIO- Corporation's Aging of Purchased Credit Impaired Loans (Detail) - USD ($) $ in Thousands	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Accounts Notes And Loans Receivable [Line Items]
PCI 30-59 Days Past Due	$ 0	[1]	$ 0	[2]
PCI 60-89 Days, Past Due	12,247	[1]	16,094	[2]
PCI 90 days or more, Past Due	28,999	[1]	23,210	[2]
Total PCI Past Due	41,246	[1]	39,304	[2]
PCI Financing Receivable, Current	124,572	[1]	134,609	[2]
Purchased Credit Impaired Loans	165,818	[1]	173,913	[2]	$ 102,604
Residential Mortgage Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
PCI 30-59 Days Past Due	0		0
PCI 60-89 Days, Past Due	11,892		16,094
PCI 90 days or more, Past Due	27,849		22,218
Total PCI Past Due	39,741		38,312
PCI Financing Receivable, Current	122,935		132,454
Purchased Credit Impaired Loans	162,676		170,766
Commercial Mortgage Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
PCI 30-59 Days Past Due	0		0
PCI 60-89 Days, Past Due	355		0
PCI 90 days or more, Past Due	1,150		992
Total PCI Past Due	1,505		992
PCI Financing Receivable, Current	1,637		2,155
Purchased Credit Impaired Loans	$ 3,142	[3]	$ 3,147	[4]

[1] According to the Corporation's delinquency policy and consistent with the instructions for the preparation of the Consolidated Financial Statements for Bank Holding Companies (FR Y-9C) required by the Federal Reserve Board, residential mortgage and commercial mortgage loans are considered past due when the borrower is in arrears two or more monthly payments. PCI residential mortgage loans and commercial mortgage loans past due 30-59 days as of December 31, 2016 amounted to $22.3 million and $0.1 million, respectively.

[2] According to the Corporation's delinquency policy and consistent with the instructions for the preparation of the Consolidated Financial Statements for Bank Holding Companies (FR Y-9C) required by the Federal Reserve Board, residential mortgage and commercial mortgage loans are considered past due when the borrower is in arrears two or more monthly payments. PCI residential mortgage loans past due 30-59 days as of December 31, 2015 amounted to $23.6 million.

[3] According to the Corporation's delinquency policy and consistent with the instructions for the preparation of the Consolidated Financial Statements for Bank Holding Companies (FR Y-9C) required by the Federal Reserve Board, residential mortgage, commercial mortgage, and construction loans are considered past due when the borrower is in arrears two or more monthly payments. FHA/VA and other government-guaranteed loans, other residential mortgage loans, commercial mortgage loans, land loans, and construction-residential loans past due 30-59 days as of December 31, 2016 amounted to $9.9 million, $142.8 million, $4.6 million, $0.7 million, and $0.4 million, respectively.

[4] According to the Corporation's delinquency policy and consistent with the instructions for the preparation of the Consolidated Financial Statements for Bank Holding Companies (FR Y-9C) required by the Federal Reserve Board, residential mortgage, commercial mortgage, and construction loans are considered past due when the borrower is in arrears two or more monthly payments. FHA/VA and other government-guaranteed loans, other residential mortgage loans, commercial mortgage loans, land loans, and construction-residential loans past-due 30-59 days as of December 31, 2015 amounted to $11.0 million, $162.9 million, $38.6 million, $5.7 million, and $0.8 million, respectively.