Investment in Securities (Schedule of Investement Securities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Investment [Line Items]
Amortized Cost	$ 342,219	$ 312,153
Gross Unrealized Gains	14,120	8,537
Gross Unrealized Losses	198	2,923
Fair Value	356,141us-gaap_AvailableForSaleSecurities	317,767us-gaap_AvailableForSaleSecurities
State and Political Subdivisions [Member]
Investment [Line Items]
Amortized Cost	338,469	308,403
Gross Unrealized Gains	14,120	8,537
Gross Unrealized Losses	198	2,923
Fair Value	352,391	314,017
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

Amount of accumulated pre-tax unrealized gains on investments in available-for-sale securities recognized in Accumulated Other Comprehensive Income (AOCI).

No definition available.

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- Definition

Amount of accumulated pre-tax unrealized loss before deducting unrealized gain on investments in available-for-sale securities recognized in Accumulated Other Comprehensive Income (AOCI).

+ References

No definition available.

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- Definition

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

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 25

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=28360136&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 5

-Subparagraph (aa)

-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27232-111563

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26610-111562

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- Definition

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

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.2)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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