Loans and Leases (Summary Of The Recorded Investment Of Company's TDRs) (Detail) - USD ($) $ in Thousands		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Financing Receivable, Modifications [Line Items]
Total recorded investment of TDR	[1]	$ 223,528	$ 272,690
Accruing TDR performing under modified terms more than one year		57.10%	55.00%
Specific reserves for TDR included in the balance of ALLL		$ 194,320	$ 174,990	$ 159,264	$ 152,573
Additional funds committed to borrowers in TDR status		459	1,133
Performing Financial Instruments [Member]
Financing Receivable, Modifications [Line Items]
Total recorded investment of TDR		147,809	171,784
Nonperforming Financial Instruments [Member]
Financing Receivable, Modifications [Line Items]
Total recorded investment of TDR		75,719	100,906
Troubled Debt Restructures [Member]
Financing Receivable, Modifications [Line Items]
Interest receivable		700	1,100
Troubled Debt Restructures [Member] | Nonperforming Financial Instruments [Member]
Financing Receivable, Modifications [Line Items]
Specific reserves for TDR included in the balance of ALLL		$ 14,583	$ 21,405

[1] Total recorded investment of TDRs exclude $0.7 million and $1.1 million at December 31, 2016 and December 31, 2015, respectively, of accrued interest receivable.