LOAN PORTFOLIO - Corporation's Aging of Loans Held for Investment Portfolio (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
Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount Net	104,313		4,791
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]
Fha Va And Other Government Guaranteed Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
30-59 Days Past Due	0	[3],[5],[6]	0	[4],[7],[8]
60-89 Days, Past Due	8,225	[3],[5],[6]	12,180	[4],[7],[8]
90 days or more, Past Due	77,238	[1],[3],[5],[6]	78,645	[2],[4],[7],[8]
Total Past Due	85,463	[3],[5],[6]	90,825	[4],[7],[8]
Financing Receivable, Current	68,847	[3],[5],[6]	104,401	[4],[7],[8]
Loans held for investment	154,310	[3],[6]	195,226	[4],[7],[8]
90 days past due and still accruing	77,238	[3],[5],[6]	78,645	[4],[7],[8]
Residential Mortgage [Member]
Accounts Notes And Loans Receivable [Line Items]
30-59 Days Past Due	0	[5]	0	[7]
60-89 Days, Past Due	87,502	[5]	88,898	[7]
90 days or more, Past Due	201,883	[1],[5]	172,286	[2],[7]
Total Past Due	289,385	[5]	261,184	[7]
Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount Net	99,535	[5]	0
Financing Receivable, Current	2,276,418	[5]	2,092,598	[7]
Loans held for investment	2,665,338	[5]	2,353,782	[7]
90 days past due and still accruing	16,858	[3],[5]	10,845	[4],[7]
Commercial And Industrial [Member]
Accounts Notes And Loans Receivable [Line Items]
30-59 Days Past Due	16,775		21,029
60-89 Days, Past Due	11,637		5,454
90 days or more, Past Due	149,037	[1]	134,233	[2]
Total Past Due	177,449		160,716
Financing Receivable, Current	2,337,935		2,867,606
Loans held for investment	2,515,384		3,028,322
90 days past due and still accruing	18,120	[3]	19,400	[4]
Commercial Mortgage Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
30-59 Days Past Due	0	[5]	0	[7]
60-89 Days, Past Due	7,306	[5]	5,428	[7]
90 days or more, Past Due	182,498	[1],[5]	126,674	[2],[7]
Total Past Due	189,804	[5]	132,102	[7]
Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount Net	3,418	[5]	0
Financing Receivable, Current	1,618,872	[5]	1,691,506	[7]
Loans held for investment	1,812,094	[5]	1,823,608	[7]
90 days past due and still accruing	12,531	[3],[5]	6,567	[4],[7]
Auto loans [Member]
Accounts Notes And Loans Receivable [Line Items]
30-59 Days Past Due	83,686		79,279
60-89 Days, Past Due	21,352		17,944
90 days or more, Past Due	22,925	[1]	21,316	[2]
Total Past Due	127,963		118,539
Financing Receivable, Current	966,671		993,781
Loans held for investment	1,094,634		1,112,320
90 days past due and still accruing	0	[3]	0	[4]
Finance Leases [Member]
Accounts Notes And Loans Receivable [Line Items]
30-59 Days Past Due	10,176		10,275
60-89 Days, Past Due	2,490		3,536
90 days or more, Past Due	4,501	[1]	3,082	[2]
Total Past Due	17,167		16,893
Financing Receivable, Current	218,948		228,430
Loans held for investment	236,115		245,323
90 days past due and still accruing	0	[3]	0	[4]
Consumer Loan [Member]
Accounts Notes And Loans Receivable [Line Items]
30-59 Days Past Due	7,240		11,710
60-89 Days, Past Due	9,335		8,691
90 days or more, Past Due	19,114	[1]	20,492	[2]
Total Past Due	35,689		40,893
Certain Loans Acquired In Transfer Not Accounted For As Debt Securities Carrying Amount Net	1,360		4,791
Financing Receivable, Current	658,789		663,192
Loans held for investment	695,838		708,876
90 days past due and still accruing	3,044	[3]	4,588	[4]
Commercial Construction [Member]
Accounts Notes And Loans Receivable [Line Items]
30-59 Days Past Due	0		0
60-89 Days, Past Due	0		0
90 days or more, Past Due	0	[1]	3,924	[2]
Total Past Due	0		3,924
Financing Receivable, Current	16,330		12,907
Loans held for investment	16,330		16,831
90 days past due and still accruing	0	[3]	0	[4]
Residential Construction [Member]
Accounts Notes And Loans Receivable [Line Items]
30-59 Days Past Due	0	[5]	0	[7]
60-89 Days, Past Due	0	[5]	0	[7]
90 days or more, Past Due	13,849	[1],[5]	27,108	[2],[7]
Total Past Due	13,849	[5]	27,108	[7]
Financing Receivable, Current	53,735	[5]	44,400	[7]
Loans held for investment	67,584	[5]	71,508	[7]
90 days past due and still accruing	0	[3],[5]	0	[4],[7]
Land Construction [Member]
Accounts Notes And Loans Receivable [Line Items]
30-59 Days Past Due	0	[5]	0	[7]
60-89 Days, Past Due	401	[5]	358	[7]
90 days or more, Past Due	16,434	[1],[5]	27,871	[2],[7]
Total Past Due	16,835	[5]	28,229	[7]
Financing Receivable, Current	40,940	[5]	52,145	[7]
Loans held for investment	57,775	[5]	80,374	[7]
90 days past due and still accruing	$ 172	[3],[5]	$ 37	[4],[7]

[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] As of September 30, 2014, includes $24.6 million of defaulted loans collateralizing Government National Mortgage Association ("GNMA") securities for which the Corporation has an unconditional option (but not an obligation) to repurchase the defaulted loans.

[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, 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.

[8] As of December 31, 2013, includes $11.5 million of defaulted loans collateralizing GNMA securities for which the Corporation has an unconditional option (but not an obligation) to repurchase the defaulted loans.