Investment in Securities (Schedule of Investement Securities) (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
Jun. 30, 2015	Dec. 31, 2014
Investment [Line Items]
Amortized Cost	$ 339,164	$ 342,219
Gross Unrealized Gains	9,858	14,120
Gross Unrealized Losses	1,202	198
Fair Value	347,820	356,141
State and Political Subdivisions [Member]
Investment [Line Items]
Amortized Cost	335,414	338,469
Gross Unrealized Gains	9,858	14,120
Gross Unrealized Losses	1,202	198
Fair Value	344,070	352,391
Certificates Of deposit [Member]
Investment [Line Items]
Amortized Cost	$ 3,750	$ 3,750
Gross Unrealized Gains
Gross Unrealized Losses
Fair Value	$ 3,750	$ 3,750

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

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This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References

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Amount of unrealized gain before deducting unrealized loss on investments in debt and equity securities classified as available-for-sale securities.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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Amount of unrealized loss before deducting unrealized gain on investments in available-for-sale securities.

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-Name Accounting Standards Codification

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