Revenue (Disaggregation of Revenue) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Disaggregation of Revenue [Line Items]
Revenue	$ 1,082,816	$ 1,060,705	$ 3,259,273	$ 2,858,756
State and local agencies(a)
Disaggregation of Revenue [Line Items]
Revenue	610,241	633,216	1,894,571	1,704,065
Federal agencies
Disaggregation of Revenue [Line Items]
Revenue	173,636	140,077	499,317	420,076
Private owners
Disaggregation of Revenue [Line Items]
Revenue	298,939	287,412	865,385	734,615
Civil
Disaggregation of Revenue [Line Items]
Revenue	545,895	520,494	1,564,548	1,424,487
Civil \| State and local agencies(a)
Disaggregation of Revenue [Line Items]
Revenue	325,543	354,819	955,157	971,259
Civil \| Federal agencies
Disaggregation of Revenue [Line Items]
Revenue	137,110	97,593	369,876	292,288
Civil \| Private owners
Disaggregation of Revenue [Line Items]
Revenue	83,242	68,082	239,515	160,940
Civil \| Mass transit (includes certain transportation and tunneling projects)
Disaggregation of Revenue [Line Items]
Revenue	341,827	293,209	883,930	842,751
Civil \| Military facilities
Disaggregation of Revenue [Line Items]
Revenue	110,214	83,811	333,137	253,189
Civil \| Commercial and industrial sites
Disaggregation of Revenue [Line Items]
Revenue	31,463	36,038	107,583	87,955
Civil \| Power and energy
Disaggregation of Revenue [Line Items]
Revenue	34,456	18,291	96,382	43,625
Civil \| Bridges
Disaggregation of Revenue [Line Items]
Revenue	1,539	72,112	91,519	154,083
Civil \| Other
Disaggregation of Revenue [Line Items]
Revenue	26,396	17,033	51,997	42,884
Building
Disaggregation of Revenue [Line Items]
Revenue	435,715	365,449	1,265,523	926,444
Building \| State and local agencies(a)
Disaggregation of Revenue [Line Items]
Revenue	241,584	197,031	736,220	510,879
Building \| Federal agencies
Disaggregation of Revenue [Line Items]
Revenue	40,616	49,853	132,753	138,678
Building \| Private owners
Disaggregation of Revenue [Line Items]
Revenue	153,515	118,565	396,550	276,887
Building \| Mass transit (includes certain transportation and tunneling projects)
Disaggregation of Revenue [Line Items]
Revenue	64,861	45,191	183,359	141,382
Building \| Other
Disaggregation of Revenue [Line Items]
Revenue	24,286	59,919	90,577	128,536
Building \| Healthcare facilities
Disaggregation of Revenue [Line Items]
Revenue	160,904	82,417	408,845	188,673
Building \| Government
Disaggregation of Revenue [Line Items]
Revenue	111,040	120,493	355,769	307,927
Building \| Education facilities
Disaggregation of Revenue [Line Items]
Revenue	74,624	57,429	226,973	159,926
Specialty Contractors
Disaggregation of Revenue [Line Items]
Revenue	101,206	174,762	429,202	507,825
Specialty Contractors \| State and local agencies(a)
Disaggregation of Revenue [Line Items]
Revenue	43,114	81,366	203,194	221,927
Specialty Contractors \| Federal agencies
Disaggregation of Revenue [Line Items]
Revenue	(4,090)	(7,369)	(3,312)	(10,890)
Specialty Contractors \| Private owners
Disaggregation of Revenue [Line Items]
Revenue	62,182	100,765	229,320	296,788
Specialty Contractors \| Mass transit (includes certain transportation and tunneling projects)
Disaggregation of Revenue [Line Items]
Revenue	22,674	18,349	119,626	70,867
Specialty Contractors \| Commercial and industrial facilities
Disaggregation of Revenue [Line Items]
Revenue	27,811	51,613	86,234	159,423
Specialty Contractors \| Multi-unit residential
Disaggregation of Revenue [Line Items]
Revenue	16,623	31,751	61,647	93,754
Specialty Contractors \| Other
Disaggregation of Revenue [Line Items]
Revenue	(14,602)	6,427	(3,057)	10,476
Specialty Contractors \| Healthcare facilities
Disaggregation of Revenue [Line Items]
Revenue	15,566	20,486	46,994	44,065
Specialty Contractors \| Government
Disaggregation of Revenue [Line Items]
Revenue	14,024	19,948	55,468	61,780
Specialty Contractors \| Education facilities
Disaggregation of Revenue [Line Items]
Revenue	8,566	7,913	22,828	704
Specialty Contractors \| Water
Disaggregation of Revenue [Line Items]
Revenue	$ 10,544	$ 18,275	$ 39,462	$ 66,756