Investment Securities (Details 3) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Investments, Debt and Equity Securities [Abstract]
Taxable interest	$ 20,944	$ 19,742	$ 17,106	$ 40,686	$ 31,705
Non-taxable interest	7,547	9,593	10,276	17,140	21,383
Dividend income	457	345	348	802	780
Total interest income on investment securities	$ 28,948	$ 29,680	$ 27,730	$ 58,628	$ 53,868

Amount of operating interest income, including amortization and accretion of premiums and discounts, on securities exempt from state, federal and other income tax.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.2)
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Amount of operating interest income, including amortization and accretion of premiums and discounts, on securities subject to state, federal and other income tax.

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Amount of dividend income on nonoperating securities.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.7(a))
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Amount before accretion (amortization) of purchase discount (premium) of interest income and dividend income on nonoperating securities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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-SubTopic 10
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