LOAN PORTFOLIO- Corporation's Aging of Purchased Credit Impaired Loans (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013		Sep. 30, 2013
Accounts Notes And Loans Receivable [Line Items]
30-59 Days Past Due	$ 117,877		$ 122,293
60-89 Days, Past Due	148,248		142,489
90 days or more, Past Due	687,479	[1]	615,631	[2]
Total Past Due	953,604		880,413
Financing Receivable, Current	8,257,485		8,750,966
Loans held for investment	9,315,402		9,636,170		9,508,634
90 days past due and still accruing	127,963	[3]	120,082	[4]
Purchased Credit Impaired Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
30-59 Days Past Due	79
60-89 Days, Past Due	11,548
90 days or more, Past Due	15,573
Total Past Due	27,200
Financing Receivable, Current	77,113
Loans held for investment	104,313
Residential Mortgage [Member]
Accounts Notes And Loans Receivable [Line Items]
30-59 Days Past Due	0	[5]	0	[6]
60-89 Days, Past Due	87,502	[5]	88,898	[6]
90 days or more, Past Due	201,883	[1],[5]	172,286	[2],[6]
Total Past Due	289,385	[5]	261,184	[6]
Financing Receivable, Current	2,276,418	[5]	2,092,598	[6]
Loans held for investment	2,665,338	[5]	2,353,782	[6]
90 days past due and still accruing	16,858	[3],[5]	10,845	[4],[6]
Residential Mortgage [Member] | Purchased Credit Impaired Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
30-59 Days Past Due	16,800	[7]
60-89 Days, Past Due	11,210	[7]
90 days or more, Past Due	14,963	[7]
Total Past Due	26,173	[7]
Financing Receivable, Current	73,362	[7]
Loans held for investment	99,535	[7]
Commercial Mortgage Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
30-59 Days Past Due	0	[5]	0	[6]
60-89 Days, Past Due	7,306	[5]	5,428	[6]
90 days or more, Past Due	182,498	[1],[5]	126,674	[2],[6]
Total Past Due	189,804	[5]	132,102	[6]
Financing Receivable, Current	1,618,872	[5]	1,691,506	[6]
Loans held for investment	1,812,094	[5]	1,823,608	[6]
90 days past due and still accruing	12,531	[3],[5]	6,567	[4],[6]
Commercial Mortgage Loans [Member] | Purchased Credit Impaired Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
30-59 Days Past Due	700	[7]
60-89 Days, Past Due	290	[7]
90 days or more, Past Due	497	[7]
Total Past Due	787	[7]
Financing Receivable, Current	2,631	[7]
Loans held for investment	3,418	[7]
Consumer Credit Card Financing Receivable [Member] | Purchased Credit Impaired Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
30-59 Days Past Due	79		377
60-89 Days, Past Due	48		354
90 days or more, Past Due	113		573
Total Past Due	240		1,304
Financing Receivable, Current	1,120		3,487
Loans held for investment	$ 1,360		$ 4,791

[1] Includes non-performing loans and accruing loans that are contractually delinquent 90 days or more (i.e., FHA/VA guaranteed loans and credit cards). Credit card loans continue to accrue finance charges fees until charged-off at 180 days.

[2] Includes non-performing loans and accruing loans that are contractually delinquent 90 days or more (i.e. FHA/VA guaranteed loans and credit cards). Credit card loans continue to accrue finance charges and fees until charged-off at 180 days.

[3] It is the Corporation's policy to report delinquent residential mortgage loans insured by the FHA or guaranteed by the VA as past-due loans 90 days and still accruing as opposed to non-performing loans since the principal repayment is insured. These balances include $41.4 million of residential mortgage loans insured by the FHA or guaranteed by the VA that are over 18 months delinquent, and are no longer accruing interest as of September 30, 2014.

[4] It is the Corporation's policy to report delinquent residential mortgage loans insured by the FHA or guaranteed by the VA as past-due loans 90 days and still accruing as opposed to non-performing loans since the principal repayment is insured. These balances include $37.0 million of residential mortgage loans insured by the FHA or guaranteed by the VA that are over 18 months delinquent, and are no longer accruing interest as of December 31, 2013.

[5] 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 government guaranteed loans, other residential mortgage loans, commercial mortgage loans, land loans and construction-residential loans past due 30-59 days amounted to $15.1 million, $179.0 million, $40.5 million, $0.5 million, and $1.7 million, respectively.

[6] 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 government guaranteed loans, other residential mortgage loans, commercial mortgage loans, land loans and construction-residential loans past due 30-59 days amounted to $23.9 million, $166.7 million, $18.4 million, $0.9 million and $2.5 million, respectively.

[7] 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 amounted to $16.8 million and $0.7 million, respectively.