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
		Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Available-for-sale securities, at fair value		$ 2,162,061	$ 1,792,078	$ 1,824,240
Impaired loans—collateral based	[1]	103,357	127,412	137,245
Municipal
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Available-for-sale securities, at fair value		269,790	238,529	176,107
Equity securities
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Available-for-sale securities, at fair value		54,208	51,139	54,852
Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Mortgage servicing rights		8,034	8,435	8,227
Fair Value, Measurements, Recurring | Municipal
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Available-for-sale securities, at fair value		269,790	238,529	176,107
Fair Value, Measurements, Recurring | Equity securities
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Available-for-sale securities, at fair value		54,208	51,139	54,852
Fair Value, Measurements, Nonrecurring [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Impaired loans—collateral based		61,713
Other real estate owned	[2]	77,499
Level 3 | Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Mortgage servicing rights		$ 8,034	8,435	8,227
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		9.00%
Fair Value Inputs, Prepayment Rate		10.00%
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		13.00%
Fair Value Inputs, Prepayment Rate		25.00%
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		9%-13%
Weighted Average of Inputs		9.15%
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		10%-25%
Weighted Average of Inputs		11.83%
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		$ 58,572	58,953	38,053
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		$ 24,996	$ 23,711	$ 24,152
Valuation Methodology		Discounted cash flows
Significant Unobservable Input		Discount rate
Range of Inputs		1.77%-2.02%
Weighted Average of Inputs		1.86%
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		1.77%
Level 3 | Fair Value, Measurements, Recurring | Equity securities | Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Discount Rate		2.02%
Level 3 | Fair Value, Measurements, Nonrecurring [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Impaired loans—collateral based		$ 61,713
Other real estate owned		$ 77,499
Level 3 | Fair Value, Measurements, Nonrecurring [Member] | Impaired Loans
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Valuation Methodology		Appraisal value
Level 3 | Fair Value, Measurements, Nonrecurring [Member] | Other Real Estate Owned
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Valuation Methodology		Appraisal value
Significant Unobservable Input		Property specific valuation adjustment
Range of Inputs		(85)%-87%
Weighted Average of Inputs		(3.58%)
Impact to valuation from an increased or higher input value		Increase
Level 3 | Fair Value, Measurements, Nonrecurring [Member] | Other Real Estate Owned | Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Property Specific Valuation Adjustment		(85.00%)
Level 3 | Fair Value, Measurements, Nonrecurring [Member] | Other Real Estate Owned | Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Property Specific Valuation Adjustment		87.00%

[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.