Fair Values Of Assets and Liabilities (Schedule Of Valuation Techniques And Significant Unobservable Inputs Used To Measure Both Recurring And Non-Recurring) (Detail) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Available-for-sale securities, at fair value		$ 770,983	$ 1,716,388	$ 1,721,030
Impaired loans—collateral based	[1]	$ 96,110	101,255	112,404
Other Real Estate Owned
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Discount for Lack of Marketability		10.00%
Municipal
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Available-for-sale securities, at fair value		$ 121,195	108,595	269,912
Equity securities
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Available-for-sale securities, at fair value		55,619	56,686	54,446
Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Mortgage servicing rights		10,128	9,092	7,852
Fair Value, Measurements, Recurring | Municipal
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Available-for-sale securities, at fair value		121,195	108,595	269,912
Fair Value, Measurements, Recurring | Equity securities
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Available-for-sale securities, at fair value		55,619	56,686	54,446
Fair Value, Measurements, Nonrecurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Impaired loans—collateral based		66,008
Other real estate owned	[2]	58,978
Level 3 | Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Mortgage servicing rights		$ 10,128	9,092	7,852
Level 3 | Fair Value, Measurements, Recurring | Mortgage Servicing Rights
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Valuation Methodology		Discounted cash flows
Level 3 | Fair Value, Measurements, Recurring | Mortgage Servicing Rights | Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Discount Rate		4.00%
Fair Value Inputs, Prepayment Rate		1.00%
Level 3 | Fair Value, Measurements, Recurring | Mortgage Servicing Rights | Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Discount Rate		7.00%
Fair Value Inputs, Prepayment Rate		46.00%
Level 3 | Fair Value, Measurements, Recurring | Mortgage Servicing Rights Discount Rate Input
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Significant Unobservable Input		Discount rate
Range of Inputs		4%-7%
Weighted Average of Inputs		6.20%
Impact to valuation from an increased or higher input value		Decrease
Level 3 | Fair Value, Measurements, Recurring | Mortgage Servicing Rights Prepayment Rate Input
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Significant Unobservable Input		Constant prepayment rate (CPR)
Range of Inputs		1%-46%
Weighted Average of Inputs		11.39%
Impact to valuation from an increased or higher input value		Decrease
Level 3 | Fair Value, Measurements, Recurring | Municipal
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Available-for-sale securities, at fair value		$ 70,242	68,613	56,049
Valuation Methodology		Bond pricing
Significant Unobservable Input		Equivalent rating
Range of Inputs		BBB-AA+
Impact to valuation from an increased or higher input value		Increase
Level 3 | Fair Value, Measurements, Recurring | Equity securities
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Available-for-sale securities, at fair value		$ 24,054	$ 25,199	$ 24,656
Valuation Methodology		Discounted cash flows
Significant Unobservable Input		Discount rate
Range of Inputs		2.81%-3.13%
Weighted Average of Inputs		2.98%
Impact to valuation from an increased or higher input value		Decrease
Level 3 | Fair Value, Measurements, Recurring | Equity securities | Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Discount Rate		2.81%
Level 3 | Fair Value, Measurements, Recurring | Equity securities | Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Discount Rate		3.13%
Level 3 | Fair Value, Measurements, Nonrecurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Impaired loans—collateral based		$ 66,008
Other real estate owned		$ 58,978
Level 3 | Fair Value, Measurements, Nonrecurring | Impaired Loans
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Valuation Methodology		Appraisal value
Significant Unobservable Input		Appraisal adjustment - cost of sale
Range of Inputs		10%
Weighted Average of Inputs		10.00%
Impact to valuation from an increased or higher input value		Decrease
Level 3 | Fair Value, Measurements, Nonrecurring | Impaired Loans | Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Discount for Lack of Marketability		10.00%
Level 3 | Fair Value, Measurements, Nonrecurring | Impaired Loans | Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Discount for Lack of Marketability		10.00%
Level 3 | Fair Value, Measurements, Nonrecurring | Other Real Estate Owned
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Valuation Methodology		Appraisal value
Significant Unobservable Input		Appraisal adjustment - cost of sale
Range of Inputs		10%
Weighted Average of Inputs		10.00%
Impact to valuation from an increased or higher input value		Decrease
Level 3 | Fair Value, Measurements, Nonrecurring | Other Real Estate Owned | Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Discount for Lack of Marketability		10.00%
Level 3 | Fair Value, Measurements, Nonrecurring | Other Real Estate Owned | Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Discount for Lack of Marketability		10.00%

[1] Impaired loans are considered by the Company to be non-accrual loans, TDRs or loans with principal and/or interest at risk, even if the loan is current with all payments of principal and interest.

[2] Fair value losses recognized, net on other real estate owned include valuation adjustments and charge-offs during the respective period.