Fair Value Measurements Fair Value Measurements, Financial Instruments Measured On a Recurring Basis, Quantitative Information (Details) - Fair Value, Measurements, Recurring [Member] - Fair Value, Inputs, Level 3 [Member] - USD ($) $ in Thousands	6 Months Ended				12 Months Ended
	Jun. 30, 2016		Jun. 30, 2015		Dec. 31, 2015
Available-for-sale securities [Member] | Municipal and other tax-exempt securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Asset, Par Value	$ 10,370		$ 10,370		$ 10,370
Fair Value Inputs, Asset, Amortized Cost	10,312		10,310		10,311
Fair Value Inputs, Asset, Fair Value	$ 9,600		$ 9,617		$ 9,610
Fair Value Measurements, Valuation Techniques	Discounted cash flows	[1]	Discounted cash flows	[2]	Discounted cash flows	[3]
Fair Value Measurements, Significant Unobservable Input	Interest rate spread		Interest rate spread		Interest rate spread
Fair Value Inputs, Assets, Discount Rate, Minimum	5.34%	[4]	5.11%	[5]	5.47%	[6]
Fair Value Inputs, Assets, Discount Rate, Maximum	5.64%	[4]	5.41%	[5]	5.77%	[6]
Fair Value Inputs, Assets, Discount Rate, Weighted Average	5.60%	[4]	5.37%	[5]	5.73%	[6]
Fair Value Inputs, Assets, Fair Value As Percentage of Par Value, Minimum	90.00%	[7]	92.50%	[8]	92.34%	[9]
Fair Value Inputs, Assets, Fair Value As Percentage of Par Value, Maximum	93.28%	[7]	92.85%	[8]	92.93%	[9]
Fair Value Inputs, Fair Value As Percentage of Par Value, Weighted Average	92.58%	[7]	92.74%	[8]	92.67%	[9]
Investment Grade Tax Exempt Securities Yield Spread Over Comparable Securities Minimum	474		502		499
Investment Grade Tax Exempt Securities Yield Spread Over Comparable Securities Maximum	513		527		541
Available-for-sale securities [Member] | Other debt securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Asset, Par Value	$ 4,400		$ 4,400		$ 4,400
Fair Value Inputs, Asset, Amortized Cost	4,400		4,400		4,400
Fair Value Inputs, Asset, Fair Value	$ 4,151		$ 4,150		$ 4,151
Fair Value Measurements, Valuation Techniques	Discounted cash flows	[1]	Discounted cash flows	[2]	Discounted cash flows	[3]
Fair Value Measurements, Significant Unobservable Input	Interest rate spread		Interest rate spread		Interest rate spread
Fair Value Inputs, Assets, Discount Rate, Minimum	5.51%	[10]	4.36%	[11]	5.80%	[12]
Fair Value Inputs, Assets, Discount Rate, Maximum	5.96%	[10]	5.69%	[11]	5.92%	[12]
Fair Value Inputs, Assets, Discount Rate, Weighted Average	5.91%	[10]	5.54%	[11]	5.90%	[12]
Fair Value Inputs, Assets, Fair Value As Percentage of Par Value, Minimum	94.32%	[7]	94.25%	[8]	94.33%	[9]
Fair Value Inputs, Assets, Fair Value As Percentage of Par Value, Maximum	94.34%	[7]	94.33%	[8]	94.34%	[9]
Fair Value Inputs, Fair Value As Percentage of Par Value, Weighted Average	94.34%	[7]	94.32%	[8]	94.34%	[9]
Average Yields On Comparable Short-term Taxable Securities Maximum	1.00%		1.00%		1.00%
Residential mortgage loans held for sale [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Asset, Amortized Cost	$ 10,518		$ 8,384		$ 8,395
Fair Value Inputs, Asset, Fair Value	$ 9,749		$ 7,973		$ 7,874
Fair Value Measurements, Valuation Techniques	Quoted prices of loans sold in securitization transactions, with a liquidity discount applied		Quoted prices of loans sold in securitization transactions, with a liquidity discount applied		Quoted prices of loans sold in securitization transactions, with a liquidity discount applied
Fair Value Measurements, Significant Unobservable Input	Liquidity discount applied to the market value of a mortgage loans qualifying for sale to U.S. government agencies.		Liquidity discount applied to the market value of a mortgage loans qualifying for sale to U.S. government agencies.		Liquidity discount applied to the market value of a mortgage loans qualifying for sale to U.S. government agencies.
Liquidity Discount on Mortgage Loans Qualifying for Sale to US Govt Agencies	92.69%		95.09%		93.79%

[1] Discounted cash flows developed using discount rates primarily based on reference to interest rate spreads for comparable securities of similar duration and credit rating as determined by the nationally-recognized rating agencies, adjusted for lack of trading volume

[2] Discounted cash flows developed using discount rates primarily based on reference to interest rate spreads for comparable securities of similar duration and credit rating as determined by the nationally-recognized rating agencies, adjusted for lack of trading volume

[3] Discounted cash flows developed using discount rates primarily based on reference to interest rate spreads for comparable securities of similar duration and credit rating as determined by the nationally-recognized rating agencies, adjusted for lack of trading volume

[4] Interest rate yields used to value investment grade tax-exempt securities represent a spread of 474 to 513 basis points over average yields for comparable tax-exempt securities.

[5] Interest rate yields used to value investment grade tax-exempt securities represent a spread of 502 to 527 basis points over average yields for comparable tax-exempt securities.

[6] Interest rate yields used to value investment grade tax-exempt securities represent a spread of 499 to 541 basis points over average yields for comparable tax-exempt securities.

[7] Represents fair value as a percentage of par value.

[8] Represents fair value as a percentage of par value.

[9] Represents fair value as a percentage of par value.

[10] Interest rate yields used to value investment grade taxable securities based on comparable short-term taxable securities which are generally yielding less than 1 percent.

[11] Interest rate yields used to value investment grade taxable securities based on comparable short-term taxable securities which are generally yielding less than 1 percent.

[12] Interest rate yields used to value investment grade taxable securities based on comparable short-term taxable securities which are generally yielding less than 1 percent.