Reportable Segments - Schedule of Revenue by Contract Type (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 29, 2024	Jul. 01, 2023	Jun. 29, 2024	Jul. 01, 2023
Segment Reporting, Revenue Reconciling Item [Line Items]
Gross revenues	$ 236,326	$ 222,638	$ 449,621	$ 406,955
INF
Segment Reporting, Revenue Reconciling Item [Line Items]
Gross revenues	100,845	96,728	191,096	184,938
BTS
Segment Reporting, Revenue Reconciling Item [Line Items]
Gross revenues	63,607	54,032	123,582	106,878
GEO
Segment Reporting, Revenue Reconciling Item [Line Items]
Gross revenues	71,874	71,878	134,943	115,139
Cost-reimbursable contracts
Segment Reporting, Revenue Reconciling Item [Line Items]
Gross revenues	212,115	202,129	405,778	369,837
Cost-reimbursable contracts | INF
Segment Reporting, Revenue Reconciling Item [Line Items]
Gross revenues	96,738	93,185	183,167	177,042
Cost-reimbursable contracts | BTS
Segment Reporting, Revenue Reconciling Item [Line Items]
Gross revenues	46,778	38,670	92,511	79,294
Cost-reimbursable contracts | GEO
Segment Reporting, Revenue Reconciling Item [Line Items]
Gross revenues	68,599	70,274	130,100	113,501
Fixed-unit price contracts
Segment Reporting, Revenue Reconciling Item [Line Items]
Gross revenues	24,211	20,509	43,843	37,118
Fixed-unit price contracts | INF
Segment Reporting, Revenue Reconciling Item [Line Items]
Gross revenues	4,107	3,543	7,929	7,896
Fixed-unit price contracts | BTS
Segment Reporting, Revenue Reconciling Item [Line Items]
Gross revenues	16,829	15,362	31,071	27,584
Fixed-unit price contracts | GEO
Segment Reporting, Revenue Reconciling Item [Line Items]
Gross revenues	$ 3,275	$ 1,604	$ 4,843	$ 1,638