Fair Value of Assets and Liabilities (Schedule of Valuation Techniques and Significant Unobservable Inputs Used to Measure Both Recurring and Nonrecurring) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) $ / Loan	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Available-for-sale Securities	$ 1,724,667	$ 1,716,388
Mortgage servicing rights	19,103	9,092	$ 8,435	$ 8,946
Derivative Assets	49,213	42,779
Impaired loans	90,516	101,255
Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Loans held-for-investment	22,137	11,361
Mortgage servicing rights	19,103	9,092
Derivative Assets	56,394	51,298
Fair Value, Measurements, Recurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Loans held-for-investment	22,137	0
Mortgage servicing rights	19,103	9,092
Derivative Assets	2,291	7,021
Fair Value, Measurements, Nonrecurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Impaired loans	64,184
Other real estate owned	45,584
Fair Value, Measurements, Nonrecurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Impaired loans	64,184
Other real estate owned	45,584
Municipal
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Available-for-sale Securities	131,809	108,595
Municipal | Fair Value, Measurements, Recurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Available-for-sale Securities	131,809	108,595
Municipal | Fair Value, Measurements, Recurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Available-for-sale Securities	$ 79,626	$ 68,613
Other Real Estate Owned
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair value inputs, discount for lack of marketability	10.00%
Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Pull Through Rate, Derivatives	35.00%
Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Pull Through Rate, Derivatives	100.00%
Loans Held For Investment | Fair Value, Measurements, Recurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Range of Inputs - Prepayment Rate	9.13%
Loans Held For Investment | Minimum | Fair Value, Measurements, Recurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Credit discount	1.00%
Loans Held For Investment | Maximum | Fair Value, Measurements, Recurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Credit discount	3.00%
Loans Held For Investment | Weighted Average | Fair Value, Measurements, Recurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Credit discount	3.03%
Bond Pricing | Municipal | Fair Value, Measurements, Recurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
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
Discounted Cash Flow | Fair Value, Measurements, Recurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Loans held-for-investment	$ 22,137
Mortgage servicing rights	$ 19,103
Discounted Cash Flow | Minimum | Fair Value, Measurements, Recurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Pull Through Rate, Derivatives	35.00%
Discounted Cash Flow | Maximum | Fair Value, Measurements, Recurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Pull Through Rate, Derivatives	100.00%
Discounted Cash Flow | Loans Held For Investment | Fair Value, Measurements, Recurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Valuation Methodology	Discounted cash flows
Significant Unobservable Input	Credit spread
Range of Inputs	1%-3%
Impact to valuation from an increased or higher input value	Decrease
Discounted Cash Flow | Loans Held For Investment | Minimum | Fair Value, Measurements, Recurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Credit discount	1.00%
Discounted Cash Flow | Loans Held For Investment | Maximum | Fair Value, Measurements, Recurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Credit discount	3.00%
Discounted Cash Flow | Loans Held For Investment | Weighted Average | Fair Value, Measurements, Recurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Range of Inputs - Prepayment Rate	3.03%
Discounted Cash Flow | Loans Held for Investment Constant Prepayment Rate | Fair Value, Measurements, Recurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Significant Unobservable Input	Constant prepayment rate (CPR)
Impact to valuation from an increased or higher input value	Decrease
Range of Inputs - Prepayment Rate	9.13%
Discounted Cash Flow | Loans Held for Investment Constant Prepayment Rate | Weighted Average | Fair Value, Measurements, Recurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Range of Inputs - Prepayment Rate	9.13%
Discounted Cash Flow | Mortgage Servicing Rights Discount Rate Input | Fair Value, Measurements, Recurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Valuation Methodology	Discounted cash flows
Significant Unobservable Input	Discount rate
Range of Inputs	4%-8%
Impact to valuation from an increased or higher input value	Decrease
Discounted Cash Flow | Mortgage Servicing Rights Discount Rate Input | Minimum | Fair Value, Measurements, Recurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Range of Inputs - Discount Rate	4.00%
Discounted Cash Flow | Mortgage Servicing Rights Discount Rate Input | Maximum | Fair Value, Measurements, Recurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Range of Inputs - Discount Rate	8.00%
Discounted Cash Flow | Mortgage Servicing Rights Discount Rate Input | Weighted Average | Fair Value, Measurements, Recurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Range of Inputs - Discount Rate	6.27%
Discounted Cash Flow | Mortgage Servicing Rights Prepayment Rate Input | Fair Value, Measurements, Recurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Significant Unobservable Input	Constant prepayment rate (CPR)
Range of Inputs	5%-80%
Impact to valuation from an increased or higher input value	Decrease
Discounted Cash Flow | Mortgage Servicing Rights Prepayment Rate Input | Minimum | Fair Value, Measurements, Recurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Range of Inputs - Prepayment Rate	5.00%
Discounted Cash Flow | Mortgage Servicing Rights Prepayment Rate Input | Maximum | Fair Value, Measurements, Recurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Range of Inputs - Prepayment Rate	80.00%
Discounted Cash Flow | Mortgage Servicing Rights Prepayment Rate Input | Weighted Average | Fair Value, Measurements, Recurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Range of Inputs - Prepayment Rate	9.25%
Discounted Cash Flow | Mortgage Servicing Rights, Cost of Servicing | Fair Value, Measurements, Recurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Significant Unobservable Input	Cost of servicing
Range of Inputs | $ / Loan	65.00
Impact to valuation from an increased or higher input value	Decrease
Discounted Cash Flow | Mortgage Servicing Rights, Cost of Servicing | Weighted Average | Fair Value, Measurements, Recurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Range of Inputs | $ / Loan	65.00
Discounted Cash Flow | Mortgage Servicing Rights, Cost of Servicing Delinquent | Fair Value, Measurements, Recurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Significant Unobservable Input	Cost of servicing - delinquent
Weighted Average of Inputs | $ / Loan	240.00
Impact to valuation from an increased or higher input value	Decrease
Discounted Cash Flow | Mortgage Servicing Rights, Cost of Servicing Delinquent | Weighted Average | Fair Value, Measurements, Recurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Weighted Average of Inputs | $ / Loan	240.00
Discounted Cash Flow | Derivative Financial Instruments, Assets | Fair Value, Measurements, Recurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Valuation Methodology	Discounted cash flows
Significant Unobservable Input	Pull-through rate
Range of Inputs	35%-100%
Impact to valuation from an increased or higher input value	Increase
Discounted Cash Flow | Derivative Financial Instruments, Assets | Weighted Average | Fair Value, Measurements, Recurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Pull Through Rate, Derivatives	85.50%
Appraisal Value | Impaired Loans | Fair Value, Measurements, Nonrecurring | Level 3
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	0.1
Impact to valuation from an increased or higher input value	Decrease
Fair value inputs, discount for lack of marketability	10.00%
Appraisal Value | Other Real Estate Owned | Fair Value, Measurements, Nonrecurring | Level 3
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	0.1
Impact to valuation from an increased or higher input value	Decrease
Fair value inputs, discount for lack of marketability	10.00%
Appraisal Value | Weighted Average | Impaired Loans | Fair Value, Measurements, Nonrecurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair value inputs, discount for lack of marketability	10.00%
Appraisal Value | Weighted Average | Other Real Estate Owned | Fair Value, Measurements, Nonrecurring | Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair value inputs, discount for lack of marketability	10.00%