Loans (Non-Accrual Loans, Segregated by Class of Loans) (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Non-accrual loans	$ 56,720	$ 89,744
Commercial and Industrial, Energy [Member]
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Non-accrual loans	590	1,150
Commercial and Industrial, Other Commercial [Member]
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Non-accrual loans	26,143	45,158
Commercial Real Estate, Buildings, Land and Other [Member]
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Non-accrual loans	27,035	38,631
Commercial Real Estate, Construction [Member]
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Non-accrual loans	0	1,100
Consumer Real Estate [Member]
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Non-accrual loans	2,207	2,773
Consumer and Other [Member]
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Non-accrual loans	$ 745	$ 932