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Fair Value Measurements (Details Textual) (USD $) In Millions, unless otherwise specified | 6 Months Ended |  |
--- | --- | --- | ---
Jun. 30, 2014 | Dec. 31, 2013 | Jun. 30, 2011
Fair Value Measurements (Textual) |  |  |
Financial instrument included in other assets | $ 1.5 | $ 1.4 |
GOGAS [Member] |  |  |
Fair Value Measurements (Textual) |  |  |
Stock option issued, exercise price |  |  | 5.0
Fair value of the GOGAS stock option |  |  |
Investment options, expiration date | Apr. 09, 2015 |  |

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- Definition Share-based compensation arrangement by share based payment award, options issued exercise price. + References No definition available. + Details
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- Definition Expiration date of the option. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Article 12 -Section 13 -Footnote 5 + Details
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- Definition Fair value of the assets less the liabilities of a derivative or group of derivatives. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=35750535&loc=d3e13433-108611 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=35750535&loc=d3e13495-108611 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958 + Details
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