INVESTMENTS INVESTMENTS - Additional Information (Details) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Dec. 31, 2017
Gain (Loss) on Investments [Line Items]
NumberOfSecuritiesInSecurityPortfolio	1,385		1,385		775
NumberOfSecuritiesInUnrealizedLossPosition	656		656		237
Available-for-sale Securities, Gross Realized Gains (Losses), Sale Proceeds	$ 216,196	$ 103,400	$ 216,200	$ 125,600
Held-to-maturity Securities, Transferred Security, at Carrying Value	367,900		367,900
Available-for-sale Securities, Gross Realized Gains	3	1,000	3	1,500
Available-for-sale Securities, Gross Realized Losses	$ 33	$ 100	$ 33	$ 100

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

For any transfer of securities categorized as held-to-maturity, this item represents the net carrying amount of the transferred security to another category of investments in debt and equity securities (trading or available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 10
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27405-111563

+ Details

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Period Type:	instant

- 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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