BENEFIT PLANS, 401(K) Employee Stock Ownership Plan (Details) - 401(k) Employee Stock Ownership Plan [Member] - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Contribution Plan [Abstract]
Percentage of first eligible compensation fully matched by employer	3.00%
Percentage of matching contribution in the form of common stock	100.00%
Percentage of the next eligible compensation matched at 50% by employer	3.00%
Percentage of matching contributions for the next eligible compensation in the form of company stock	50.00%
(Income)/expense recognized under plan	$ 6.1	$ 5.9	$ 5.3
Interest credit contribution expense recognized for 401(k) plan	$ 1.1	$ 0.9	$ 0.8
Minimum [Member]
Defined Contribution Plan [Abstract]
Contribution from eligible compensation	1.00%
Maximum [Member]
Defined Contribution Plan [Abstract]
Contribution from eligible compensation	90.00%

The amount of the interest credit contribution expense recognized during the period for defined contribution plans.

No definition available.

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- Definition

The percentage of contribution that employees are allowed to make from eligible compensation under 401(k) Employee Stock Ownership Plan.

+ References

No definition available.

+ Details

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- Definition

The percentage of compensation eligible for full matching contribution by employer.

+ References

No definition available.

+ Details

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- Definition

The percentage of matching contribution.

+ References

No definition available.

+ Details

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- Definition

Percentage of the matching contributions for the next eligible compensation.

+ References

No definition available.

+ Details

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- Definition

The percentage of the next eligible compensation matched at 50% by employer.

+ References

No definition available.

+ Details

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- References

No definition available.

+ Details

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- Definition

Amount of cost for defined contribution plan.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 70
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942

+ Details

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- Details

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- Details

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