Contract Balances and Contract Costs - Disaggregation of Revenue by Service Type (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 30, 2020	Nov. 01, 2019	Oct. 30, 2020	Nov. 01, 2019
Disaggregation of Revenue [Line Items]
Net revenue	$ 141,641	$ 141,332	$ 421,298	$ 410,779
Managed Security Solutions revenue
Disaggregation of Revenue [Line Items]
Net revenue	108,265	109,344	320,881	311,210
Security and Risk Consulting revenue
Disaggregation of Revenue [Line Items]
Net revenue	$ 33,376	$ 31,988	$ 100,417	$ 99,569