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Revenue Recognition - General (Details) - item	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2017	Dec. 30, 2017	Dec. 31, 2016
Concentration Risk
Number of broad areas of consulting services	2	2
Revenue Benchmark | Revenue Concentration Risk
Concentration Risk
Number of broad areas of consulting services	2	2
Percentage of consolidated revenues	100.00%	100.00%	100.00%	100.00%

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- Definition

Number of broad areas in consulting services.

+ References

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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.

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For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=84177426&loc=d3e6351-108592

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Name Accounting Standards Codification
-Topic 275
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-Topic 825
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-Paragraph 21
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