Loans (Schedule Of Aging Of Loan Portfolio) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	$ 41,507	$ 44,174
60-89 Days Past Due	20,277	30,426
Greater than 90 Days Past Due	6,726	5,006
Non-accrual Loans	201,197	242,319
Total Past Due	269,707	321,925
Loans Not Past Due	6,789,505	6,546,696
Loans	7,059,212	6,868,621
Commercial Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	1,683	7,037
60-89 Days Past Due		2,990
Non-accrual Loans	30,661	31,498
Total Past Due	32,344	41,525
Loans Not Past Due	1,835,931	1,399,642
Loans	1,868,275	1,441,167
Real Estate Construction Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	20,326	14,634
60-89 Days Past Due		15,425
Greater than 90 Days Past Due		4,175
Non-accrual Loans	46,012	53,937
Total Past Due	66,338	88,171
Loans Not Past Due	171,034	321,815
Loans	237,372	409,986
Commercial Mortgage Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	13,627	12,569
60-89 Days Past Due	20,277	9,430
Greater than 90 Days Past Due	6,726	831
Non-accrual Loans	107,784	144,596
Total Past Due	148,414	167,426
Loans Not Past Due	3,600,483	3,772,635
Loans	3,748,897	3,940,061
Residential Mortgage And Equity Lines [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	5,871	9,934
60-89 Days Past Due		2,581
Non-accrual Loans	16,740	12,288
Total Past Due	22,611	24,803
Loans Not Past Due	1,164,358	1,036,527
Loans	1,186,969	1,061,330
Installment And Other Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Not Past Due	17,699	16,077
Loans	$ 17,699	$ 16,077