Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Amortized cost and fair value of securities held to maturity
Amortized Cost	$ 458,400	$ 430,163
Gross Unrealized Gains	16,662	15,438
Gross Unrealized Losses	(1,309)	(3,113)
Fair Value	473,753	442,488
Obligations of other U.S. Government agencies and corporations
Amortized cost and fair value of securities held to maturity
Amortized Cost	101,155	125,081
Gross Unrealized Gains	26	10
Gross Unrealized Losses	(1,214)	(2,915)
Fair Value	99,967	122,176
Obligations of states and political subdivisions
Amortized cost and fair value of securities held to maturity
Amortized Cost	357,245	305,082
Gross Unrealized Gains	16,636	15,428
Gross Unrealized Losses	(95)	(198)
Fair Value	$ 373,786	$ 320,312

Amount of accumulated unrealized gain on investments in debt securities classified as held-to-maturity.

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Amount of accumulated unrealized loss on investments in debt securities classified as held-to-maturity.

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Amount before other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity.

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Fair value of investments in debt securities classified as held-to-maturity.

+ References

Reference 1: 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 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
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-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27232-111563

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27232-111563

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