Number of broad areas in consulting services.

No definition available.

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- Definition

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
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- Definition

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

+ References

No definition available.

+ Details

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- Definition

Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

+ 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(13))
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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.

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- Definition

Aggregate revenue during the period from services rendered in the normal course of business, after deducting allowances and discounts.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1(d))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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Business Segment and Geographic Information (Details) $ in Thousands		3 Months Ended		9 Months Ended		12 Months Ended
	Apr. 13, 2016 segment	Sep. 30, 2017 USD ($) item	Oct. 01, 2016 USD ($)	Sep. 30, 2017 USD ($) item	Oct. 01, 2016 USD ($)	Dec. 30, 2017 segment	Dec. 31, 2016 USD ($)
Business segment and geographic information
Number of Broad Areas of Consulting Services \| item		2		2
Number of business segments \| segment	2					1
Revenues		$ 91,325	$ 81,691	$ 273,059	$ 245,210
Total Long-lived assets (property and equipment, net)		$ 41,062		$ 41,062			$ 36,381
Revenue Benchmark \| Revenue Concentration Risk
Business segment and geographic information
Number of Broad Areas of Consulting Services \| item		2		2
Percentage of consolidated revenues		100.00%		100.00%		100.00%	100.00%
United States
Business segment and geographic information
Revenues		$ 70,910	63,955	$ 217,608	189,832
Total Long-lived assets (property and equipment, net)		34,005		34,005			$ 30,735
United Kingdom
Business segment and geographic information
Revenues		13,572	12,463	40,444	40,421
Total Long-lived assets (property and equipment, net)		5,560		5,560			5,253
Other
Business segment and geographic information
Revenues		6,843	5,273	15,007	14,957
Total Long-lived assets (property and equipment, net)		1,497		1,497			393
Total foreign
Business segment and geographic information
Revenues		20,415	$ 17,736	55,451	$ 55,378
Total Long-lived assets (property and equipment, net)		$ 7,057		$ 7,057			$ 5,646