INVESTMENT SECURITIES - Narrative (Details) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2019 USD ($) position	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($) position	Jun. 30, 2018 USD ($)
Investments, Debt and Equity Securities [Abstract]
Percentage of debt securities considered to be of investment-grade	96.00%		96.00%
Maximum percentage of any general obligation bonds in one state			16.00%
Securities in unrealized loss positions, number of positions	330		330
Securities, number of positions	1,460		1,460
Other-than-temporary impairments \| $	$ 0.0	$ 0.0	$ 0.0	$ 0.0

Debt Securities, Available-for-sale, Securities, Number of Positions

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- Definition

Maximum percentage of any general obligation bonds in one state

+ References

No definition available.

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- Definition

Percentage of Total Debt Securities

+ References

No definition available.

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- Definition

Number of investments in debt securities measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (b)(3)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27290-111563

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 50
-Paragraph 4
-Subparagraph (b)(3)
-URI http://asc.fasb.org/extlink&oid=118955579&loc=SL82922888-210455

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- Definition

The amount by which the fair value of an investment is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 8A
-URI http://asc.fasb.org/extlink&oid=118954083&loc=SL6284422-111562

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- References

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