INVESTMENTS INVESTMENTS - Additional Information (Details) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Dec. 31, 2016
Gain (Loss) on Investments [Line Items]
NumberOfSecuritiesInSecurityPortfolio	759		759		706
NumberOfSecuritiesInUnrealizedLossPosition	207		207		255
Available-for-sale Securities, Gross Realized Gains (Losses), Sale Proceeds	$ 53.9	$ 99.4	$ 179.6	$ 206.9
Available-for-sale Securities, Gross Realized Gains	0.4	0.8	1.8	1.2
Available-for-sale Securities, Gross Realized Losses	$ 0.1	$ 0.5	$ 0.2	$ 1.0

The total number of securities included in the investment securities portfolio.

No definition available.

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- Definition

The total number of securities included in the investment securities portfolio that include net accumulated unrealized losses.

+ References

No definition available.

+ Details

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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

+ Details

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- Definition

The total amount of proceeds received for the sale of securities, categorized neither as held-to-maturity nor trading securities, during the reporting period.

+ References

+ Details

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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.

+ References

+ Details

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- Definition

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.

+ Details

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