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LONG-TERM DEBT (Details) (USD $) | 12 Months Ended
--- | ---
Dec. 31, 2013 | Dec. 31, 2012 | Dec. 31, 2011
Debt Instrument [Line Items] |  |  |
Maximum borrowing capacity |  | $ 430,000,000 |
Credit Facility Costs | 0 | 6,139,000 | 0
2012 Credit Facility [Member] |  |  |
Debt Instrument [Line Items] |  |  |
Maximum borrowing capacity |  | 430,000,000 |
Maturity date |  | Oct. 31, 2017 |
Credit Facility Costs |  | 6,139,000 |
Commitment fees and interest paid | 9,700,000 | 2,900,000 |
Undrawn amount | 180,000,000 | 180,000,000 |
2005 Credit Facility [Member] |  |  |
Debt Instrument [Line Items] |  |  |
Maximum borrowing capacity |  | 300,000,000 |
Commitment fees and interest paid |  |  | 1,900,000
2005 Revised Credit Facility [Member] |  |  |
Debt Instrument [Line Items] |  |  |
Maximum borrowing capacity | 500,000,000 |  |
Repayment obligation | $ 0 |  |
Term of Debt Instrument | 5 years |  |

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- Definition Repayment obligation prior to the final maturity of the credit facility. + References No definition available. + Details
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- Definition The period time between the last modification of the credit facility and the final maturity. + References No definition available. + Details
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- Details
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- Definition Amount of the fee for available but unused credit capacity under the credit facility. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 + Details
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- Definition Date the credit facility terminates, in CCYY-MM-DD format. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 + Details
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- Definition Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 + Details
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- Definition Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 + Details
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- Definition The cash outflow for loan and debt issuance costs. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Financing Activities -URI http://asc.fasb.org/extlink&oid=6513228 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3291-108585 + Details
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