Investment in Securities (Schedule of Investment Securities) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Investment [Line Items]
Amortized Cost	$ 357,240	$ 363,157
Gross Unrealized Gains	$ 15,905	12,552
Gross Unrealized Losses		13
Fair Value	$ 373,145	375,696
State and Political Subdivisions [Member]
Investment [Line Items]
Amortized Cost	349,614	356,531
Gross Unrealized Gains	$ 15,905	12,552
Gross Unrealized Losses		13
Fair Value	$ 365,519	369,070
Certificates of Deposit [Member]
Investment [Line Items]
Amortized Cost	$ 7,626	$ 6,626
Gross Unrealized Gains
Gross Unrealized Losses
Fair Value	$ 7,626	$ 6,626

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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- 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=65884222&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=73527792&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=66010992&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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