LONG-TERM DEBT (Details) - USD ($)	1 Months Ended
Jan. 31, 2018	Jun. 30, 2018
Junior Subordinated Debt
Debt instrument
Interest rate percentage	6.375%
Face amount	$ 400,000,000.0
Proceeds from issuance of debt	394,900,000
Revolving Credit Facility
Debt instrument
Long-term debt		$ 459,500,000
Weighted average interest rate		3.30%
Revolving Credit Facility \| Line of Credit
Debt instrument
Additional borrowing capacity		$ 1,038,100,000
6.050% Notes Due January 2018
Debt instrument
Principal amount repaid	300,000,000
Accrued interest amount repaid	$ 9,100,000
Interest rate percentage	6.05%
2.650% Notes due November 2018
Debt instrument
Interest rate percentage		2.65%
Long-term debt		$ 400,000,000
LIBOR \| Junior Subordinated Debt
Debt instrument
Variable rate	4.02%

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

No definition available.

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- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
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-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
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-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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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.

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- Definition

Weighted average interest rate of debt outstanding.

+ References

No definition available.

+ Details

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- Definition

The increase (decrease) during the reporting period in interest payable, which represents the amount owed to note holders, bond holders, and other parties for interest earned on loans or credit extended to the reporting entity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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-Section 45
-Paragraph 28
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- Definition

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

+ References

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- Definition

The cash inflow from the issuance of long-term debt that is not secured by collateral. Excludes proceeds from tax exempt unsecured debt.

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- Definition

The cash outflow for a borrowing supported by a written promise to pay an obligation.

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