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INCOME TAXES, Income Tax Reform (Details) - USD ($) $ in Millions | 3 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2017 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Income Tax Disclosure [Line Items] |  |  |  |  |
Tax provision computed at the federal statutory rate, percentage |  |  | 35.00% | 35.00% | 35.00%
Untaxed accumulated earnings | $ 199.9 |  | $ 199.9 |  |
Income tax rate on illiquid assets |  |  | 8.00% |  |
Income tax rate on liquid assets |  |  | 15.50% |  |
Estimated transition tax | 17.5 |  |  |  |
Estimated transition tax, after tax credits | 16.0 |  |  |  |
Number of years of transition tax payable |  |  | 8 years |  |
Transition tax, interest free, payable in first five year |  |  | 8.00% |  |
Transition tax, interest free, payable in sixth year |  |  | 15.00% |  |
Transition tax, interest free, payable in seventh year |  |  | 20.00% |  |
Transition tax, interest free, payable in eighth year |  |  | 25.00% |  |
Decrease related to deferred tax assets | $ 2.0 |  | $ 6.3 |  |
Decrease related to deferred tax liabilities |  |  | 4.2 |  |
Net adjustment to deferred income tax expense |  |  | $ 2.1 |  |
Plan [Member] |  |  |  |  |
Income Tax Disclosure [Line Items] |  |  |  |  |
Tax provision computed at the federal statutory rate, percentage |  | 21.00% |  |  |

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