Loans (Net (Charge-Offs)/Recoveries, Segregated by Class of Loans) (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net charge-offs	$ (32,597)	$ (15,774)	$ (43,614)
Commercial and Industrial, Energy [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net charge-offs	(913)	4	6
Commercial and Industrial, Other Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net charge-offs	(28,431)	(13,627)	(29,158)
Commercial Real Estate, Buildings, Land and Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net charge-offs	(381)	698	(8,980)
Commercial Real Estate, Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net charge-offs	256	78	(454)
Consumer Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net charge-offs	(719)	(638)	(2,293)
Consumer and Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net charge-offs	$ (2,409)	$ (2,289)	$ (2,735)