Troubled debt restructuring according to their accruing status (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Non Covered Loans [Member]
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	$ 894,875	$ 1,150,946
Non Covered Loans [Member] | Commercial Portfolio Segment Member
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	192,266	313,767
Non Covered Loans [Member] | Construction Member
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	15,654	13,279
Non Covered Loans [Member] | Legacy [Member]
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	3,949	5,978
Non Covered Loans [Member] | Mortgages
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	547,685	678,105
Non Covered Loans [Member] | Finance Leases Portfolio Segment Member
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	3,818	4,881
Non Covered Loans [Member] | Consumer Portfolio Segment Member
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	131,503	134,936
Covered Under Loss Sharing Agreements With F D I C [Member]
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	25,208	58,640
Covered Under Loss Sharing Agreements With F D I C [Member] | Commercial Portfolio Segment Member
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	19,239	50,213
Covered Under Loss Sharing Agreements With F D I C [Member] | Construction Member
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	5,232	7,435
Covered Under Loss Sharing Agreements With F D I C [Member] | Mortgages
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	337	369
Covered Under Loss Sharing Agreements With F D I C [Member] | Consumer Portfolio Segment Member
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	400	623
Non Accrual [Member] | Non Covered Loans [Member]
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	173,508	509,585
Non Accrual [Member] | Non Covered Loans [Member] | Commercial Portfolio Segment Member
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	78,690	208,119
Non Accrual [Member] | Non Covered Loans [Member] | Construction Member
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	12,731	10,310
Non Accrual [Member] | Non Covered Loans [Member] | Legacy [Member]
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	3,949	5,978
Non Accrual [Member] | Non Covered Loans [Member] | Mortgages
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	65,347	273,042
Non Accrual [Member] | Non Covered Loans [Member] | Finance Leases Portfolio Segment Member
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	2,395	3,155
Non Accrual [Member] | Non Covered Loans [Member] | Consumer Portfolio Segment Member
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	10,396	8,981
Non Accrual [Member] | Covered Under Loss Sharing Agreements With F D I C [Member]
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	17,244	11,832
Non Accrual [Member] | Covered Under Loss Sharing Agreements With F D I C [Member] | Commercial Portfolio Segment Member
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	11,785	4,071
Non Accrual [Member] | Covered Under Loss Sharing Agreements With F D I C [Member] | Construction Member
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	5,232	7,435
Non Accrual [Member] | Covered Under Loss Sharing Agreements With F D I C [Member] | Mortgages
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	189	220
Non Accrual [Member] | Covered Under Loss Sharing Agreements With F D I C [Member] | Consumer Portfolio Segment Member
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	38	106
Accrual [Member] | Non Covered Loans [Member]
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	721,367	641,361
Accrual [Member] | Non Covered Loans [Member] | Commercial Portfolio Segment Member
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	113,576	105,648
Accrual [Member] | Non Covered Loans [Member] | Construction Member
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	2,923	2,969
Accrual [Member] | Non Covered Loans [Member] | Legacy [Member]
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	0	0
Accrual [Member] | Non Covered Loans [Member] | Mortgages
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	482,338	405,063
Accrual [Member] | Non Covered Loans [Member] | Finance Leases Portfolio Segment Member
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	1,423	1,726
Accrual [Member] | Non Covered Loans [Member] | Consumer Portfolio Segment Member
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	121,107	125,955
Accrual [Member] | Covered Under Loss Sharing Agreements With F D I C [Member]
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	7,964	46,808
Accrual [Member] | Covered Under Loss Sharing Agreements With F D I C [Member] | Commercial Portfolio Segment Member
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	7,454	46,142
Accrual [Member] | Covered Under Loss Sharing Agreements With F D I C [Member] | Construction Member
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	0	0
Accrual [Member] | Covered Under Loss Sharing Agreements With F D I C [Member] | Mortgages
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	148	149
Accrual [Member] | Covered Under Loss Sharing Agreements With F D I C [Member] | Consumer Portfolio Segment Member
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	$ 362	$ 517