Revenue (Disaggregation of Revenue) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disaggregation of Revenue [Line Items]
Revenue	$ 1,048,987	$ 776,300
State and local agencies
Disaggregation of Revenue [Line Items]
Revenue	607,467	435,710
Federal agencies
Disaggregation of Revenue [Line Items]
Revenue	159,945	139,612
Private owners
Disaggregation of Revenue [Line Items]
Revenue	281,575	200,978
Civil
Disaggregation of Revenue [Line Items]
Revenue	472,165	349,870
Civil | State and local agencies
Disaggregation of Revenue [Line Items]
Revenue	283,995	213,427
Civil | Federal agencies
Disaggregation of Revenue [Line Items]
Revenue	113,454	95,984
Civil | Private owners
Disaggregation of Revenue [Line Items]
Revenue	74,716	40,459
Civil | Mass transit (includes certain transportation and tunneling projects)
Disaggregation of Revenue [Line Items]
Revenue	252,516	188,460
Civil | Military facilities
Disaggregation of Revenue [Line Items]
Revenue	105,144	85,567
Civil | Commercial and industrial sites
Disaggregation of Revenue [Line Items]
Revenue	39,490	22,726
Civil | Bridges
Disaggregation of Revenue [Line Items]
Revenue	27,672	30,645
Civil | Power and energy
Disaggregation of Revenue [Line Items]
Revenue	26,198	10,176
Civil | Other
Disaggregation of Revenue [Line Items]
Revenue	21,145	12,296
Building
Disaggregation of Revenue [Line Items]
Revenue	411,942	229,653
Building | State and local agencies
Disaggregation of Revenue [Line Items]
Revenue	246,519	136,601
Building | Federal agencies
Disaggregation of Revenue [Line Items]
Revenue	46,052	41,735
Building | Private owners
Disaggregation of Revenue [Line Items]
Revenue	119,371	51,317
Building | Mass transit (includes certain transportation and tunneling projects)
Disaggregation of Revenue [Line Items]
Revenue	61,175	33,320
Building | Other
Disaggregation of Revenue [Line Items]
Revenue	10,250	(63,124)
Building | Government
Disaggregation of Revenue [Line Items]
Revenue	130,611	89,620
Building | Health care facilities
Disaggregation of Revenue [Line Items]
Revenue	111,987	50,417
Building | Education facilities
Disaggregation of Revenue [Line Items]
Revenue	68,159	48,077
Building | Sports and entertainment
Disaggregation of Revenue [Line Items]
Revenue	15,639	13,466
Building | Commercial and industrial facilities
Disaggregation of Revenue [Line Items]
Revenue	11,369	38,271
Building | Hospitality and gaming
Disaggregation of Revenue [Line Items]
Revenue	2,752	19,606
Specialty Contractors
Disaggregation of Revenue [Line Items]
Revenue	164,880	196,777
Specialty Contractors | State and local agencies
Disaggregation of Revenue [Line Items]
Revenue	76,953	85,682
Specialty Contractors | Federal agencies
Disaggregation of Revenue [Line Items]
Revenue	439	1,893
Specialty Contractors | Private owners
Disaggregation of Revenue [Line Items]
Revenue	87,488	109,202
Specialty Contractors | Mass transit (includes certain transportation and tunneling projects)
Disaggregation of Revenue [Line Items]
Revenue	48,126	47,545
Specialty Contractors | Other
Disaggregation of Revenue [Line Items]
Revenue	9,939	3,275
Specialty Contractors | Government
Disaggregation of Revenue [Line Items]
Revenue	22,953	21,069
Specialty Contractors | Health care facilities
Disaggregation of Revenue [Line Items]
Revenue	16,710	9,531
Specialty Contractors | Commercial and industrial facilities
Disaggregation of Revenue [Line Items]
Revenue	28,210	54,227
Specialty Contractors | Multi-unit residential
Disaggregation of Revenue [Line Items]
Revenue	24,726	32,796
Specialty Contractors | Water
Disaggregation of Revenue [Line Items]
Revenue	$ 14,216	$ 28,334