Fair Value Measurement Of Assets And Liabilities (Carrying Amounts And Estimated Fair Values Of Financial Instruments) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2012 Carrying Amount [Member]	Mar. 31, 2011 Carrying Amount [Member]	Mar. 31, 2012 Fair Value [Member]	Mar. 31, 2011 Fair Value [Member]	Mar. 31, 2012 Level 1 [Member] Carrying Amount [Member]		Mar. 31, 2011 Level 1 [Member] Carrying Amount [Member]		Mar. 31, 2012 Level 1 [Member] Fair Value [Member]		Mar. 31, 2011 Level 1 [Member] Fair Value [Member]		Mar. 31, 2012 Level 2 [Member] Carrying Amount [Member]	Mar. 31, 2011 Level 2 [Member] Carrying Amount [Member]	Mar. 31, 2012 Level 2 [Member] Fair Value [Member]	Mar. 31, 2011 Level 2 [Member] Fair Value [Member]	Mar. 31, 2012 Level 3 [Member] Carrying Amount [Member]	Mar. 31, 2011 Level 3 [Member] Carrying Amount [Member]	Mar. 31, 2012 Level 3 [Member] Fair Value [Member]	Mar. 31, 2011 Level 3 [Member] Fair Value [Member]	Mar. 31, 2012 U.S. Treasury Securities [Member] Level 1 [Member] Carrying Amount [Member]	Mar. 31, 2011 U.S. Treasury Securities [Member] Level 1 [Member] Carrying Amount [Member]	Mar. 31, 2012 U.S. Treasury Securities [Member] Level 1 [Member] Fair Value [Member]	Mar. 31, 2011 U.S. Treasury Securities [Member] Level 1 [Member] Fair Value [Member]	Mar. 31, 2012 Obligations Of States And Political Subdivisions [Member] Level 2 [Member] Carrying Amount [Member]	Mar. 31, 2011 Obligations Of States And Political Subdivisions [Member] Level 2 [Member] Carrying Amount [Member]	Mar. 31, 2012 Obligations Of States And Political Subdivisions [Member] Level 2 [Member] Fair Value [Member]	Mar. 31, 2011 Obligations Of States And Political Subdivisions [Member] Level 2 [Member] Fair Value [Member]	Mar. 31, 2012 Residential Mortgage-Backed Securities [Member] Level 2 [Member] Carrying Amount [Member]	Mar. 31, 2011 Residential Mortgage-Backed Securities [Member] Level 2 [Member] Carrying Amount [Member]	Mar. 31, 2012 Residential Mortgage-Backed Securities [Member] Level 2 [Member] Fair Value [Member]	Mar. 31, 2011 Residential Mortgage-Backed Securities [Member] Level 2 [Member] Fair Value [Member]	Mar. 31, 2012 Trust Preferred Securities [Member] Level 2 [Member] Carrying Amount [Member]	Mar. 31, 2011 Trust Preferred Securities [Member] Level 2 [Member] Carrying Amount [Member]	Mar. 31, 2012 Trust Preferred Securities [Member] Level 2 [Member] Fair Value [Member]	Mar. 31, 2011 Trust Preferred Securities [Member] Level 2 [Member] Fair Value [Member]	Mar. 31, 2012 Corporate And Other Debt Securities [Member] Level 2 [Member] Carrying Amount [Member]	Mar. 31, 2011 Corporate And Other Debt Securities [Member] Level 2 [Member] Carrying Amount [Member]	Mar. 31, 2012 Corporate And Other Debt Securities [Member] Level 2 [Member] Fair Value [Member]	Mar. 31, 2011 Corporate And Other Debt Securities [Member] Level 2 [Member] Fair Value [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Cash and due from banks							$ 466,616		$ 372,566		$ 466,616		$ 372,566
Interest bearing deposits with banks	34,219	6,483					34,219		6,483		34,219		6,483
Total investment securities held to maturity			1,878,462	1,958,916	1,940,444	2,027,197																	99,982	100,018	110,564	113,859	442,551	433,284	460,131	453,201	1,090,434	1,180,104	1,133,217	1,230,993	193,298	193,312	180,521	174,753	52,197	52,198	56,011	54,391
Net loans																			11,016,652	9,665,839	10,974,970	9,645,517
Accrued interest receivable	57,349	52,527					57,349		52,527		57,349		52,527
Federal Reserve Bank and Federal Home Loan Bank stock							141,815	[1]	129,669	[1]	141,815	[1]	129,669	[1]
Deposits without stated maturities							8,246,548		7,171,718		8,246,548		7,171,718
Deposits with stated maturities															2,710,636	2,501,384	2,767,444	2,557,119
Short-term borrowings							410,749		212,849		410,757		215,179
Long-term borrowings															2,724,731	2,726,099	3,103,096	3,154,150
Junior subordinated debentures issued to capital trusts, Carrying Amount															40,805	25,120
Junior subordinated debentures issued to capital trusts, Fair Value																	42,492	25,620
Accrued interest payable							$ 4,026	[2]	$ 3,798	[2]	$ 4,026	[2]	$ 3,798	[2]

[1] Included in other assets.

[2] Included in accrued expenses and other liabilities.