Loans (Activity In Allowance For Loan Losses By Portfolio Segment) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	$ 105,648	$ 122,741	$ 110,147	$ 126,316
Provision for loan losses	2,500	9,010	5,955	27,445
Charge-offs	(8,957)	(19,966)	(24,747)	(47,690)
Recoveries	6,210	3,648	14,046	9,362
Net (charge-offs) recoveries	(2,747)	(16,318)	(10,701)	(38,328)
Ending balance	105,401	115,433	105,401	115,433
Commercial And Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	53,475	56,566	42,774	57,789
Provision for loan losses	2,723	3,920	18,275	14,245
Charge-offs	(5,837)	(15,084)	(13,323)	(28,258)
Recoveries	1,181	1,483	3,816	3,109
Net (charge-offs) recoveries	(4,656)	(13,601)	(9,507)	(25,149)
Ending balance	51,542	46,885	51,542	46,885
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	27,631	20,901	20,912	28,534
Provision for loan losses	(2,682)	1,194	5,882	1,440
Charge-offs	(520)	(1,689)	(3,715)	(10,261)
Recoveries	3,212	406	4,562	1,099
Net (charge-offs) recoveries	2,692	(1,283)	847	(9,162)
Ending balance	27,641	20,812	27,641	20,812
Consumer Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	5,235	3,683	3,540	3,223
Provision for loan losses	315	513	2,295	1,865
Charge-offs	(209)	(834)	(1,104)	(2,113)
Recoveries	53	84	663	471
Net (charge-offs) recoveries	(156)	(750)	(441)	(1,642)
Ending balance	5,394	3,446	5,394	3,446
Consumer And Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	3,649	12,611	12,635	11,974
Provision for loan losses	880	880	(7,133)	3,208
Charge-offs	(2,391)	(2,359)	(6,605)	(7,058)
Recoveries	1,764	1,675	5,005	4,683
Net (charge-offs) recoveries	(627)	(684)	(1,600)	(2,375)
Ending balance	3,902	12,807	3,902	12,807
Unallocated Financing Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	15,658	28,980	30,286	24,796
Provision for loan losses	1,264	2,503	(13,364)	6,687
Ending balance	$ 16,922	$ 31,483	$ 16,922	$ 31,483