Revenue (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
REVENUE	$ 3,880,227	$ 3,790,755	$ 4,641,830
Net revenue recognized related to performance obligations satisfies (or partially satisfied) in prior periods	214,200	292,300	37,500
Fixed price
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
REVENUE	2,728,175	2,466,326	3,140,148
Cost plus fee and other
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
REVENUE	294,838	351,605	232,192
Civil
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
REVENUE	1,883,865	1,734,882	2,095,760
Performance obligation amount	$ 4,200,000	4,400,000
Civil | Minimum
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation period range	3 years
Civil | Maximum
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation period range	5 years
Civil | Fixed price
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
REVENUE	$ 1,618,081	1,441,547	1,815,079
Civil | Cost plus fee and other
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
REVENUE	33,883	17,900	9,450
Building
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
REVENUE	1,302,539	1,242,571	1,428,102
Performance obligation amount	2,200,000	2,200,000
Building | Fixed price
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
REVENUE	532,950	349,318	336,128
Building | Cost plus fee and other
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
REVENUE	237,051	297,313	205,002
Specialty Contractors
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
REVENUE	693,823	813,302	1,117,968
Performance obligation amount	1,100,000	1,300,000
Specialty Contractors | Fixed price
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
REVENUE	577,144	675,461	988,941
Specialty Contractors | Cost plus fee and other
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
REVENUE	$ 23,904	$ 36,392	$ 17,740
Building and Specialty Contractors | Minimum
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation period range	1 year
Building and Specialty Contractors | Maximum
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation period range	3 years