Revenue (Disaggregation Of Revenue) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Disaggregation of Revenue [Line Items]
Revenue	$ 1,060,705	$ 1,070,926	$ 2,858,756	$ 2,884,107
State and local agencies
Disaggregation of Revenue [Line Items]
Revenue	633,216	625,555	1,704,065	1,656,019
Federal agencies
Disaggregation of Revenue [Line Items]
Revenue	140,077	145,091	420,076	361,796
Private owners
Disaggregation of Revenue [Line Items]
Revenue	287,412	300,280	734,615	866,292
Civil
Disaggregation of Revenue [Line Items]
Revenue	520,494	500,905	1,424,487	1,295,322
Civil | State and local agencies
Disaggregation of Revenue [Line Items]
Revenue	354,819	375,566	971,259	1,008,819
Civil | Federal agencies
Disaggregation of Revenue [Line Items]
Revenue	97,593	97,741	292,288	211,426
Civil | Private owners
Disaggregation of Revenue [Line Items]
Revenue	68,082	27,598	160,940	75,077
Civil | Mass transit (includes certain transportation and tunneling projects)
Disaggregation of Revenue [Line Items]
Revenue	293,209	311,702	842,751	794,414
Civil | Military facilities
Disaggregation of Revenue [Line Items]
Revenue	83,811	66,063	253,189	176,212
Civil | Bridges
Disaggregation of Revenue [Line Items]
Revenue	72,112	86,042	154,083	212,362
Civil | Commercial and industrial sites
Disaggregation of Revenue [Line Items]
Revenue	36,038	19,813	87,955	44,583
Civil | Other
Disaggregation of Revenue [Line Items]
Revenue	35,324	17,285	86,509	67,751
Building
Disaggregation of Revenue [Line Items]
Revenue	365,449	318,050	926,444	915,639
Building | State and local agencies
Disaggregation of Revenue [Line Items]
Revenue	197,031	136,082	510,879	349,245
Building | Federal agencies
Disaggregation of Revenue [Line Items]
Revenue	49,853	42,367	138,678	130,867
Building | Private owners
Disaggregation of Revenue [Line Items]
Revenue	118,565	139,601	276,887	435,527
Building | Mass transit (includes certain transportation and tunneling projects)
Disaggregation of Revenue [Line Items]
Revenue	45,191	40,783	141,382	111,431
Building | Other
Disaggregation of Revenue [Line Items]
Revenue	13,274	13,194	(35,821)	34,145
Building | Government
Disaggregation of Revenue [Line Items]
Revenue	120,493	88,624	307,927	248,405
Building | Health care facilities
Disaggregation of Revenue [Line Items]
Revenue	82,417	48,602	188,673	134,439
Building | Education facilities
Disaggregation of Revenue [Line Items]
Revenue	57,429	41,538	159,926	102,574
Building | Commercial and industrial facilities
Disaggregation of Revenue [Line Items]
Revenue	11,358	60,711	65,655	149,106
Building | Hospitality and gaming
Disaggregation of Revenue [Line Items]
Revenue	19,158	17,455	55,743	118,450
Building | Sports and entertainment
Disaggregation of Revenue [Line Items]
Revenue	16,129	7,143	42,959	17,089
Specialty Contractors
Disaggregation of Revenue [Line Items]
Revenue	174,762	251,971	507,825	673,146
Specialty Contractors | State and local agencies
Disaggregation of Revenue [Line Items]
Revenue	81,366	113,907	221,927	297,955
Specialty Contractors | Federal agencies
Disaggregation of Revenue [Line Items]
Revenue	(7,369)	4,983	(10,890)	19,503
Specialty Contractors | Private owners
Disaggregation of Revenue [Line Items]
Revenue	100,765	133,081	296,788	355,688
Specialty Contractors | Mass transit (includes certain transportation and tunneling projects)
Disaggregation of Revenue [Line Items]
Revenue	18,349	95,281	70,867	289,703
Specialty Contractors | Other
Disaggregation of Revenue [Line Items]
Revenue	14,340	30,254	11,180	61,532
Specialty Contractors | Health care facilities
Disaggregation of Revenue [Line Items]
Revenue	19,948	17,738	61,780	43,356
Specialty Contractors | Commercial and industrial facilities
Disaggregation of Revenue [Line Items]
Revenue	51,613	50,213	159,423	116,514
Specialty Contractors | Multi-unit residential
Disaggregation of Revenue [Line Items]
Revenue	31,751	31,461	93,754	84,642
Specialty Contractors | Water
Disaggregation of Revenue [Line Items]
Revenue	18,275	20,274	66,756	55,693
Specialty Contractors | Health care facilities
Disaggregation of Revenue [Line Items]
Revenue	$ 20,486	$ 6,750	$ 44,065	$ 21,706