LOAN PORTFOLIO - Breakdown Between Accrual and Nonaccrual Status of TDRs (Detail) - USD ($) $ in Thousands	Sep. 30, 2017		Jun. 30, 2017	Dec. 31, 2016		Sep. 30, 2016	Jun. 30, 2016	Dec. 31, 2015
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	$ 585,795		$ 568,543	$ 647,048		$ 656,318	$ 670,991	$ 661,591
Non Accrual [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	196,961	[1]		262,161	[2]
Accrual [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	388,834			384,887
Non Fha Va Residential Mortgage Loans [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	363,269			375,809
Non Fha Va Residential Mortgage Loans [Member] | Non Accrual [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	82,013	[1]		80,153	[2]
Non Fha Va Residential Mortgage Loans [Member] | Accrual [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	281,256			295,656
Commercial Mortgage Loans [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	51,645			48,742
Commercial Mortgage Loans [Member] | Non Accrual [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	17,950	[1]		16,402	[2]
Commercial Mortgage Loans [Member] | Accrual [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	33,695			32,340
Commercial And Industrial Loan [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	88,023			133,521
Commercial And Industrial Loan [Member] | Non Accrual [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	49,946	[1]		115,025	[2]
Commercial And Industrial Loan [Member] | Accrual [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	38,077			18,496
Consumer Auto Loans [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	23,504			24,875
Consumer Auto Loans [Member] | Non Accrual [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	7,905	[1]		8,622	[2]
Consumer Auto Loans [Member] | Accrual [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	15,599			16,253
Finance Leases [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	2,271			2,647
Finance Leases [Member] | Non Accrual [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	226	[1]		105	[2]
Finance Leases [Member] | Accrual [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	2,045			2,542
Other Consumer Loans [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	12,183			14,842
Other Consumer Loans [Member] | Non Accrual [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	1,620	[1]		2,974	[2]
Other Consumer Loans [Member] | Accrual [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	10,563			11,868
Commercial Construction [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	35,520			36,893
Commercial Construction [Member] | Non Accrual [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	35,520	[1]		36,893	[2]
Commercial Construction [Member] | Accrual [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0			0
Residential Construction [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	217			357
Residential Construction [Member] | Non Accrual [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	217	[1]		357	[2]
Residential Construction [Member] | Accrual [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0			0
Land Construction [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	9,163			9,362
Land Construction [Member] | Non Accrual [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	1,564	[1]		1,630	[2]
Land Construction [Member] | Accrual [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	$ 7,599			$ 7,732

[1] Included in non-accrual loans are $82.8 million in loans that are performing under the terms of the restructuring agreement but are reported in nonaccrual status until the restructured loans meet the criteria of sustained payment performance under the revised terms for reinstatement to accrual status and are deemed fully collectible.

[2] Included in non-accrual loans are $110.6 million in loans that are performing under the terms of the restructuring agreement but are reported in non-accrual status until the restructured loans meet the criteria of sustained payment performance under the revised terms for reinstatement to accrual status and are deemed fully collectible.