Fair Values Of Assets And Liabilities (Summary Of Changes In Level 3 Assets And Liabilities Measured At Fair Value On A Recurring Basis) (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
U.S. Government Agencies Debt Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance
Total net gains (losses) included in Net income				[1]				[2]
Total net gains (losses) included in Other comprehensive income
Purchases
issuances
Sales
Settlements
Net transfers into Level 3			7,959	[3]			7,959	[4]
Ending Balance			7,959				7,959
Municipal Bonds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	25,537		24,525		24,211		16,416
Total net gains (losses) included in Net income				[1]				[2]
Total net gains (losses) included in Other comprehensive income	14				50		(748)
Purchases	10,204		6,492		14,044		15,630
issuances
Sales			(1,871)				(6,655)
Settlements			(1,230)		(148)		(1,230)
Net transfers into Level 3			(2,511)	[3]	(2,402)	[5]	1,992	[4]
Ending Balance	35,755		25,405		35,755		25,405
Corporate Notes And Other [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance			16,313				9,841
Total net gains (losses) included in Net income				[1]			(274)	[2]
Total net gains (losses) included in Other comprehensive income
Purchases			500				7,246
issuances
Sales
Settlements			(192)				(192)
Net transfers into Level 3			(10,712)	[3]			(10,712)	[4]
Ending Balance			5,909				5,909
Collateralized Mortgage Backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance			2,684				2,460
Total net gains (losses) included in Net income				[1]			(53)	[2]
Total net gains (losses) included in Other comprehensive income
Purchases			333				610
issuances
Sales
Settlements			(65)				(65)
Net transfers into Level 3				[3]
Ending Balance			2,952				2,952
Equity Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	20,218		30,891		18,971		28,672
Total net gains (losses) included in Net income				[1]				[2]
Total net gains (losses) included in Other comprehensive income	2,037				3,284		419
Purchases							1,800
issuances
Sales
Settlements
Net transfers into Level 3				[3]
Ending Balance	22,255		30,891		22,255		30,891
Categories of Investments, Marketable Securities, Trading Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance			172				4,372
Total net gains (losses) included in Net income				[1]				[2]
Total net gains (losses) included in Other comprehensive income
Purchases
issuances
Sales			(147)				(4,347)
Settlements
Net transfers into Level 3				[3]
Ending Balance			25				25
Mortgage Servicing Rights
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	6,647		8,762		6,700		8,762
Total net gains (losses) included in Net income	(371)	[1]	(2,022)	[1]	(424)	[1]	(2,022)	[2]
Total net gains (losses) included in Other comprehensive income
Purchases
issuances
Sales
Settlements
Net transfers into Level 3				[3]
Ending Balance	$ 6,276		$ 6,740		$ 6,276		$ 6,740

[1] Changes in the balance of mortgage servicing rights are recorded as a component of mortgage banking revenue in non-interest income.

[2] Income for Corporate notes and other debt and mortgage-backed is recognized as a component of interest income on securities. Changes in the balance of mortgage servicing rights are recorded as a component of mortgage banking revenue in non-interest income.

[3] The transfer of U.S. Agency, Municipal securities and Corporate notes and other debt into/(out of) Level 3 is the result of the use of unobservable inputs that reflect the Company's own assumptions that market participants would use in pricing these securities.

[4] The transfer of U.S. Agency, Municipal securities and Corporate notes and other debt into/(out of) Level 3 is the result of the use of unobservable inputs that reflect the Company's own assumptions that market participants would use in pricing these securities. Transfers into/(out of) Level 3 are recognized at the end of the reporting period.

[5] During the first quarter of 2012, one municipal security was transferred out of Level 3 into Level 2 as observable market information was available that market participants would use in pricing these securities. Transfers out of Level 3 are recognized at the end of the reporting period.