Securities - Additional Information (Details) $ in Millions	3 Months Ended	12 Months Ended
Mar. 31, 2016 USD ($) security	Dec. 31, 2015 USD ($) security
Securities Pledged
Average loss on securities, percent	0.41%	0.55%
Securitites in unrealized loss position \| security	6	6
Repurchase Agreements
Securities Pledged
Amortized cost of securities pledged	$ 14.2	$ 14.9
Securities pledged and available to be sold under repurchase agreements, fair value	14.3	15.0
Derivative
Securities Pledged
Amortized cost of securities pledged	2.6	2.8
Securities pledged and available to be sold under repurchase agreements, fair value	2.7	2.9
Securities pledged to various Federal Reserve Districts relating to deposits of bankruptcy trustees
Securities Pledged
Amortized cost of securities	106.6	97.3
Fair value of pledged securities	106.6	97.1
Public Deposits
Securities Pledged
Fair value of pledged securities	$ 2.0	$ 2.2

Amortized Cost of Securities Pledged to Various Federal Reserve Districts.

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- Definition

Fair Value of Securities Pledged to Various Federal Reserve Districts.

+ References

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- Definition

Represents the average loss on securities in an unrealized loss position expressed as a percentage of amortized cost basis.

+ References

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Amortized Cost of financial instrument held by the entity.

+ References

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- Definition

Number of investment positions in available-for-sale investments in a continuous unrealized loss position for which an other-than-temporary impairment (OTTI) has not been recognized in the income statement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (b)(3)
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27290-111563

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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Fair value of financial instrument held by the entity for its own account (proprietary securities) for trading or investment purposes that are carried at fair value and pledged to counterparties as collateral for financing transactions.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 50
-Paragraph 1A
-Subparagraph (b)(1)(i)
-URI http://asc.fasb.org/extlink&oid=55761124&loc=SL6224234-111729

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6467456&loc=d3e113888-111728

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