Reportable Segments - Revenue by Customer Type (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 28, 2020	Mar. 30, 2019
Segment Reporting, Revenue Reconciling Item [Line Items]
Gross revenues	$ 165,480	$ 117,335
INF
Segment Reporting, Revenue Reconciling Item [Line Items]
Gross revenues	84,426	77,273
BTS
Segment Reporting, Revenue Reconciling Item [Line Items]
Gross revenues	43,112	40,062
GEO
Segment Reporting, Revenue Reconciling Item [Line Items]
Gross revenues	37,942	0
Public and quasi-public sector
Segment Reporting, Revenue Reconciling Item [Line Items]
Gross revenues	109,734	83,445
Public and quasi-public sector | INF
Segment Reporting, Revenue Reconciling Item [Line Items]
Gross revenues	65,385	68,129
Public and quasi-public sector | BTS
Segment Reporting, Revenue Reconciling Item [Line Items]
Gross revenues	17,836	15,316
Public and quasi-public sector | GEO
Segment Reporting, Revenue Reconciling Item [Line Items]
Gross revenues	26,513	0
Private sector
Segment Reporting, Revenue Reconciling Item [Line Items]
Gross revenues	55,746	33,890
Private sector | INF
Segment Reporting, Revenue Reconciling Item [Line Items]
Gross revenues	19,041	9,144
Private sector | BTS
Segment Reporting, Revenue Reconciling Item [Line Items]
Gross revenues	25,276	24,746
Private sector | GEO
Segment Reporting, Revenue Reconciling Item [Line Items]
Gross revenues	$ 11,429	$ 0