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Long-Term Debt (Details) - USD ($) | 6 Months Ended |
--- | --- | ---
Jun. 30, 2018 | Dec. 31, 2014
Debt Instrument [Line Items] |  |
Line of Credit Facility, Maximum Borrowing Capacity, Current | $ 175,000,000.0 | $ 250,000,000.0
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage | 0.0625% |
Debt Instrument, Covenant, Leverage Ratio | 2 |
Debt Covenant, Minimum Net Income Requirement | $ 1.00 |
Debt Covenant, Minimum Tangible Net Worth | 175,000,000.0 |
Letters of Credit Outstanding, Amount | 3,700,000 |
Line of Credit Facility, Current Borrowing Capacity | $ 171,300,000 |
London Interbank Offered Rate (LIBOR) [Member] |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Basis Spread on Variable Rate | 0.625% |
Prime Rate [Member] |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Basis Spread on Variable Rate | 0.00% |

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- Definition Debt Covenant, Minimum Net Income Requirement + References No definition available. + Details
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- Definition Debt Covenant, Minimum Tangible Net Worth + References No definition available. + Details
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- Definition Debt Instrument, Covenant, Leverage Ratio + References No definition available. + Details
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- Definition Percentage points added to the reference rate to compute the variable rate on the debt instrument. + References No definition available. + Details
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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. + Details
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- Definition The total amount of the contingent obligation under letters of credit outstanding as of the reporting date. + References No definition available. + Details
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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 Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -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 + 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://fasb.org/us-gaap/role/ref/legacyRef -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 + Details
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- Definition The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility. + References No definition available. + Details
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