Troubled debt restructuring according to their accruing status (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Non Covered Loans [Member]
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	$ 953,745	$ 950,337
Non Covered Loans [Member] | Commercial Portfolio Segment Member
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	172,224	189,602
Non Covered Loans [Member] | Construction [Member]
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	14,684	11,290
Non Covered Loans [Member] | Legacy [Member]
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	949	949
Non Covered Loans [Member] | Mortgages [Member]
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	638,430	618,143
Non Covered Loans [Member] | Finance Leases Portfolio Segment Member
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	2,455	2,893
Non Covered Loans [Member] | Consumer [Member]
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	125,003	127,460
Covered Under Loss Sharing Agreements With F D I C [Member]
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	6,419	21,448
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	2,645	17,406
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	3,232	3,464
Covered Under Loss Sharing Agreements With F D I C [Member] | Mortgages [Member]
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	368	335
Covered Under Loss Sharing Agreements With F D I C [Member] | Consumer [Member]
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	174	243
Non Accrual [Member] | Non Covered Loans [Member]
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	184,148	188,104
Non Accrual [Member] | Non Covered Loans [Member] | Commercial Portfolio Segment Member
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	64,319	80,140
Non Accrual [Member] | Non Covered Loans [Member] | Construction [Member]
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	14,283	10,865
Non Accrual [Member] | Non Covered Loans [Member] | Legacy [Member]
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	949	949
Non Accrual [Member] | Non Covered Loans [Member] | Mortgages [Member]
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	92,019	82,786
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	1,477	2,623
Non Accrual [Member] | Non Covered Loans [Member] | Consumer [Member]
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	11,101	10,741
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	6,032	13,692
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	2,631	10,017
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	3,232	3,464
Non Accrual [Member] | Covered Under Loss Sharing Agreements With F D I C [Member] | Mortgages [Member]
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	157	189
Non Accrual [Member] | Covered Under Loss Sharing Agreements With F D I C [Member] | Consumer [Member]
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	12	22
Accrual [Member] | Non Covered Loans [Member]
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	769,597	762,233
Accrual [Member] | Non Covered Loans [Member] | Commercial Portfolio Segment Member
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	107,905	109,462
Accrual [Member] | Non Covered Loans [Member] | Construction [Member]
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	401	425
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 [Member]
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	546,411	535,357
Accrual [Member] | Non Covered Loans [Member] | Finance Leases Portfolio Segment Member
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	978	270
Accrual [Member] | Non Covered Loans [Member] | Consumer [Member]
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	113,902	116,719
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	387	7,756
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	14	7,389
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 [Member]
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	211	146
Accrual [Member] | Covered Under Loss Sharing Agreements With F D I C [Member] | Consumer [Member]
Troubled Debt Restructuring, Debtor, Current Period [Line Items]
Financing Receivable Modifications Recorded Investment	$ 162	$ 221