Securities (Held-to-maturity Securities) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Schedule of Held-to-maturity Securities [Line Items]
Total investment securities	$ 236,283	$ 253,550
Gross Unrealized Gains	9,554	12,460
Gross Unrealized Losses	(496)	(516)
Estimated Fair Value	245,341	265,494
Obligations of states and political subdivisions
Schedule of Held-to-maturity Securities [Line Items]
Total investment securities	236,283	253,550
Gross Unrealized Gains	9,554	12,460
Gross Unrealized Losses	(496)	(516)
Estimated Fair Value	$ 245,341	$ 265,494

Amount of investment in debt security measured at amortized cost (held-to-maturity).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Amount of accumulated unrecognized gain on investment in debt security measured at amortized cost (held-to-maturity).

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-Name Accounting Standards Codification
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Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity).

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Fair value of investment in debt security measured at amortized cost (held-to-maturity).

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