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	6 Months Ended
	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Available-for-sale securities, at fair value	$ 637,663	$ 1,716,388	$ 2,162,061
Impaired loans—collateral based	$ 95,976	101,255	103,357
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	$ 111,640	108,595	269,790
Equity securities
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Available-for-sale securities, at fair value	56,579	56,686	54,208
Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
MSRs	13,382	9,092	8,034
Fair Value, Measurements, Recurring | Municipal
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Available-for-sale securities, at fair value	111,640	108,595	269,790
Fair Value, Measurements, Recurring | Equity securities
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Available-for-sale securities, at fair value	56,579	56,686	54,208
Fair Value, Measurements, Nonrecurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Impaired loans—collateral based	67,837
Other real estate owned	51,046
Level 3 | Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
MSRs	$ 13,382	9,092	8,034
Level 3 | Fair Value, Measurements, Recurring | Mortgage Servicing Rights | Weighted Average
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Discount Rate	5.20%
Fair Value Inputs, Prepayment Rate	11.67%
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	3.00%
Fair Value Inputs, Prepayment Rate	2.00%
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	6.00%
Fair Value Inputs, Prepayment Rate	47.00%
Level 3 | Fair Value, Measurements, Recurring | Mortgage Servicing Rights Discount Rate Input
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Valuation Methodology	Discounted cash flows
Significant Unobservable Input	Discount rate
Range of Inputs	3%-6%
Impact to valuation from an increased or higher input value	Decrease
Level 3 | Fair Value, Measurements, Recurring | Mortgage Servicing Rights Discount Rate Input | Weighted Average
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Discount Rate	5.20%
Level 3 | Fair Value, Measurements, Recurring | Mortgage Servicing Rights Discount Rate Input | Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Discount Rate	3.00%
Level 3 | Fair Value, Measurements, Recurring | Mortgage Servicing Rights Discount Rate Input | Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Discount Rate	6.00%
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	2%-47%
Impact to valuation from an increased or higher input value	Decrease
Level 3 | Fair Value, Measurements, Recurring | Mortgage Servicing Rights Prepayment Rate Input | Weighted Average
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Prepayment Rate	11.67%
Level 3 | Fair Value, Measurements, Recurring | Mortgage Servicing Rights Prepayment Rate Input | Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Prepayment Rate	2.00%
Level 3 | Fair Value, Measurements, Recurring | Mortgage Servicing Rights Prepayment Rate Input | Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Prepayment Rate	47.00%
Level 3 | Fair Value, Measurements, Recurring | Municipal
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Available-for-sale securities, at fair value	$ 69,812	68,613	58,572
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	$ 25,187	$ 25,199	$ 24,996
Valuation Methodology	Discounted cash flows
Significant Unobservable Input	Discount rate
Range of Inputs	2.16%-2.81%
Impact to valuation from an increased or higher input value	Decrease
Level 3 | Fair Value, Measurements, Recurring | Equity securities | Weighted Average
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Discount Rate	2.48%
Level 3 | Fair Value, Measurements, Recurring | Equity securities | Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Discount Rate	2.16%
Level 3 | Fair Value, Measurements, Recurring | Equity securities | Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Discount Rate	2.81%
Level 3 | Fair Value, Measurements, Nonrecurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Impaired loans—collateral based	$ 67,837
Other real estate owned	$ 51,046
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
Impact to valuation from an increased or higher input value	Decrease
Fair Value Inputs, Discount for Lack of Marketability	10.00%
Level 3 | Fair Value, Measurements, Nonrecurring | Impaired Loans | Weighted Average
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
Impact to valuation from an increased or higher input value	Decrease
Fair Value Inputs, Discount for Lack of Marketability	10.00%
Level 3 | Fair Value, Measurements, Nonrecurring | Other Real Estate Owned | Weighted Average
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair Value Inputs, Discount for Lack of Marketability	10.00%