LOAN PORTFOLIO - Selected Information on TDRs Includes Recorded Investment by Loan Class and Modification Type (Detail) - USD ($) $ in Thousands	Sep. 30, 2017		Jun. 30, 2017	Dec. 31, 2016		Sep. 30, 2016	Jun. 30, 2016	Dec. 31, 2015
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	$ 585,795		$ 568,543	$ 647,048		$ 656,318	$ 670,991	$ 661,591
Interest Rate Below Market [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	35,605			37,645
Maturity of Term Extension [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	41,505			88,535
Combination of reduction in interest rate and extension of maturity [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	342,999			355,812
Forgiveness of principal and/or interest [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	35,864			38,055
Other [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	129,822	[1]		127,001	[2]
Non Fha Va Residential Mortgage Loans [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	363,269			375,809
Non Fha Va Residential Mortgage Loans [Member] | Interest Rate Below Market [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	26,013			29,254
Non Fha Va Residential Mortgage Loans [Member] | Maturity of Term Extension [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	8,308			8,373
Non Fha Va Residential Mortgage Loans [Member] | Combination of reduction in interest rate and extension of maturity [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	268,035			280,588
Non Fha Va Residential Mortgage Loans [Member] | Forgiveness of principal and/or interest [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	0			0
Non Fha Va Residential Mortgage Loans [Member] | Other [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	60,913	[1]		57,594	[2]
Commercial Mortgage Loans [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	51,645			48,742
Commercial Mortgage Loans [Member] | Interest Rate Below Market [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	6,639			6,044
Commercial Mortgage Loans [Member] | Maturity of Term Extension [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	2,124			2,007
Commercial Mortgage Loans [Member] | Combination of reduction in interest rate and extension of maturity [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	32,697			30,005
Commercial Mortgage Loans [Member] | Forgiveness of principal and/or interest [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	0			0
Commercial Mortgage Loans [Member] | Other [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	10,185	[1]		10,686	[2]
Commercial And Industrial Loan [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	88,023			133,521
Commercial And Industrial Loan [Member] | Interest Rate Below Market [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	2,115			2,111
Commercial And Industrial Loan [Member] | Maturity of Term Extension [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	20,749			66,830
Commercial And Industrial Loan [Member] | Combination of reduction in interest rate and extension of maturity [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	16,026			16,359
Commercial And Industrial Loan [Member] | Forgiveness of principal and/or interest [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	94			863
Commercial And Industrial Loan [Member] | Other [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	49,039	[1]		47,358	[2]
Construction Loans [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	44,900
Consumer Auto Loans [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	23,504			24,875
Consumer Auto Loans [Member] | Interest Rate Below Market [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	0			0
Consumer Auto Loans [Member] | Maturity of Term Extension [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	1,371			1,706
Consumer Auto Loans [Member] | Combination of reduction in interest rate and extension of maturity [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	14,721			14,698
Consumer Auto Loans [Member] | Forgiveness of principal and/or interest [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	0			0
Consumer Auto Loans [Member] | Other [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	7,412	[1]		8,471	[2]
Finance Leases [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	2,271			2,647
Finance Leases [Member] | Interest Rate Below Market [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	0			0
Finance Leases [Member] | Maturity of Term Extension [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	255			366
Finance Leases [Member] | Combination of reduction in interest rate and extension of maturity [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	2,016			2,281
Finance Leases [Member] | Forgiveness of principal and/or interest [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	0			0
Finance Leases [Member] | Other [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	[1]		0	[2]
Other Consumer Loans [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	12,183			14,842
Other Consumer Loans [Member] | Interest Rate Below Market [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	821			236
Other Consumer Loans [Member] | Maturity of Term Extension [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	2,053			2,518
Other Consumer Loans [Member] | Combination of reduction in interest rate and extension of maturity [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	7,323			9,662
Other Consumer Loans [Member] | Forgiveness of principal and/or interest [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	250			299
Other Consumer Loans [Member] | Other [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	1,736	[1]		2,127	[2]
Commercial Construction [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	35,520			36,893
Commercial Construction [Member] | Interest Rate Below Market [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	0			0
Commercial Construction [Member] | Maturity of Term Extension [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	0			0
Commercial Construction [Member] | Combination of reduction in interest rate and extension of maturity [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	0			0
Commercial Construction [Member] | Forgiveness of principal and/or interest [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	35,520			36,893
Commercial Construction [Member] | Other [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	[1]		0	[2]
Residential Construction [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	217			357
Residential Construction [Member] | Interest Rate Below Market [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	0			0
Residential Construction [Member] | Maturity of Term Extension [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	0			0
Residential Construction [Member] | Combination of reduction in interest rate and extension of maturity [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	0			0
Residential Construction [Member] | Forgiveness of principal and/or interest [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	0			0
Residential Construction [Member] | Other [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	217	[1]		357	[2]
Land Construction [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	9,163			9,362
Land Construction [Member] | Interest Rate Below Market [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	17			0
Land Construction [Member] | Maturity of Term Extension [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	6,645			6,735
Land Construction [Member] | Combination of reduction in interest rate and extension of maturity [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	2,181			2,219
Land Construction [Member] | Forgiveness of principal and/or interest [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	0			0
Land Construction [Member] | Other [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Modifications, Recorded Investment	$ 320	[1]		$ 408	[2]

[1] Other concessions granted by the Corporation include deferral of principal and/or interest payments for a period longer than what would be considered insignificant, payment plans under judicial stipulation, or a combination of the concessions listed in the table.

[2] Other concessions granted by the Corporation include deferral of principal and/or interest payments for a period longer than what would be considered insignificant, payment plans under judicial stipulation or a combination of the concessions listed in the table.