Stock Based Compensation - Schedule of assumptions for fair value of options at the date of the grant (Details)	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation [Abstract]
Expected option life	3 years 8 months 12 days	5 years 8 months 12 days
Weighted average risk-free interest rate	2.20%	1.30%
Weighted average expected volatility	36.00%	33.00%
Expected dividend yield	0.00%	0.00%

No definition available.

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- Definition

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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+ Details

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- Definition

The risk-free interest rate assumption that is used in valuing an option on its own shares.

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+ Details

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- Definition

Weighted average expected volatility rate of share-based compensation awards.

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+ Details

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- Definition

Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(i)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.D.2)
-URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809

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