Loans (Schedule Of Allowance For Loan Losses By Portfolio Segment And Based On Impairment Method) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for impairment, Allowance	$ 7,552	$ 13,116
Loans individually evaluated for impairment, Balance	321,973	366,740
Loans collectively evaluated for impairment, Allowance	198,728	232,115
Loans collectively evaluated for impairment, Balance	6,737,239	6,501,881
Total allowance	206,280	245,231
Total balance	7,059,212	6,868,621
Commercial Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for impairment, Allowance	3,336	2,540
Loans individually evaluated for impairment, Balance	45,781	33,555
Loans collectively evaluated for impairment, Allowance	62,322	61,379
Loans collectively evaluated for impairment, Balance	1,822,494	1,407,612
Total allowance	65,658	63,919
Total balance	1,868,275	1,441,167
Real Estate Construction Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for impairment, Allowance		7,470
Loans individually evaluated for impairment, Balance	78,766	77,691
Loans collectively evaluated for impairment, Allowance	21,749	35,791
Loans collectively evaluated for impairment, Balance	158,606	332,295
Total allowance	21,749	43,261
Total balance	237,372	409,986
Commercial Mortgage Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for impairment, Allowance	2,969	3,106
Loans individually evaluated for impairment, Balance	177,058	248,059
Loans collectively evaluated for impairment, Allowance	105,052	125,241
Loans collectively evaluated for impairment, Balance	3,571,839	3,692,002
Total allowance	108,021	128,347
Total balance	3,748,897	3,940,061
Residential Mortgage And Equity Lines [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans individually evaluated for impairment, Allowance	1,247
Loans individually evaluated for impairment, Balance	20,368	7,435
Loans collectively evaluated for impairment, Allowance	9,548	9,668
Loans collectively evaluated for impairment, Balance	1,166,601	1,053,895
Total allowance	10,795	9,668
Total balance	1,186,969	1,061,330
Consumer And Other [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans collectively evaluated for impairment, Allowance	57	36
Loans collectively evaluated for impairment, Balance	17,699	16,077
Total allowance	57	36
Total balance	$ 17,699	$ 16,077