Securities - Amortized Cost and Fair Value, Held to Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Amortized cost and fair value of securities held to maturity
Amortized Cost	$ 0	$ 356,282
Gross Unrealized Gains	0	8,576
Gross Unrealized Losses	0	(1,965)
Fair Value	0	362,893
Obligations of other U.S. Government agencies and corporations
Amortized cost and fair value of securities held to maturity
Amortized Cost	0	14,101
Gross Unrealized Gains	0	4
Gross Unrealized Losses	0	(187)
Fair Value	0	13,918
Obligations of states and political subdivisions
Amortized cost and fair value of securities held to maturity
Amortized Cost	0	342,181
Gross Unrealized Gains	0	8,572
Gross Unrealized Losses	0	(1,778)
Fair Value	$ 0	$ 348,975

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

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- Definition

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

+ References

+ Details

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- Definition

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

+ References

No definition available.

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- Definition

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=82897076&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
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27232-111563

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27232-111563

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