Summary of Significant Accounting Policies - Revenue by Vertical Market as Percentage of Total Revenue (Details) - Customer Concentration Risk [Member] - Sales Revenue, Services, Net [Member]	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Oct. 02, 2015	Sep. 30, 2016	Oct. 02, 2015
Concentration Risk [Line Items]
Total revenue	100.00%	100.00%	100.00%	100.00%
Technology Service Providers [Member]
Concentration Risk [Line Items]
Total revenue	36.30%	32.40%	35.20%	30.30%
Manufacturing [Member]
Concentration Risk [Line Items]
Total revenue	24.60%	24.90%	24.10%	26.30%
Healthcare [Member]
Concentration Risk [Line Items]
Total revenue	17.10%	23.70%	18.40%	24.20%
Financial Services [Member]
Concentration Risk [Line Items]
Total revenue	7.60%	7.00%	7.60%	7.00%
Energy [Member]
Concentration Risk [Line Items]
Total revenue	4.60%	5.10%	5.30%	5.30%
General Markets [Member]
Concentration Risk [Line Items]
Total revenue	9.80%	6.90%	9.40%	6.90%