Securities - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Mortgage and asset-backed securities and collateralized mortgage obligations, weighted average duration	4 years 1 month 6 days
Net unrealized gains on equity securities	$ 214
Proceeds from sale of available-for-sale securities	$ 0	$ 44,855
Available-for-sale securities, gross realized gains		267
Available-for-sale securities, gross realized losses		$ (1,300)
Held-to-maturity securities, depreciation, percentage of amortized cost basis	2.90%

Equity Securities, FV-NI, Unrealized Gain

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- Definition

Held-to-maturity Securities, Debt Maturities, Weighted Average Term

+ References

No definition available.

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- Definition

Held-to-maturity, Securities in Unrealized Loss Positions, Qualitative Disclosure, Depreciation, Percentage of Amortized Cost Basis

+ References

No definition available.

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- Definition

This item represents the gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 9
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27357-111563

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- Definition

This item represents the gross loss realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

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- References

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- Definition

The cash inflow associated with the sale of debt and equity securities classified as available-for-sale securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=82896770&loc=d3e26853-111562

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (a),(b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3179-108585

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