Revenue (Disaggregation Of Revenue) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Disaggregation of Revenue [Line Items]
Revenue	$ 1,070,926	$ 1,178,222	$ 2,884,107	$ 3,605,060
State and local agencies
Disaggregation of Revenue [Line Items]
Revenue	625,555	688,272	1,656,019	1,995,967
Federal agencies
Disaggregation of Revenue [Line Items]
Revenue	145,091	113,833	361,796	341,390
Private owners
Disaggregation of Revenue [Line Items]
Revenue	300,280	376,117	866,292	1,267,703
Civil
Disaggregation of Revenue [Line Items]
Revenue	500,905	546,218	1,295,322	1,577,145
Civil | State and local agencies
Disaggregation of Revenue [Line Items]
Revenue	375,566	478,720	1,008,819	1,350,555
Civil | Federal agencies
Disaggregation of Revenue [Line Items]
Revenue	97,741	48,680	211,426	149,648
Civil | Private owners
Disaggregation of Revenue [Line Items]
Revenue	27,598	18,818	75,077	76,942
Civil | Mass transit (includes certain transportation and tunneling projects)
Disaggregation of Revenue [Line Items]
Revenue	311,702	386,913	794,414	1,062,322
Civil | Bridges
Disaggregation of Revenue [Line Items]
Revenue	86,042	67,117	212,362	179,059
Civil | Military defense facilities
Disaggregation of Revenue [Line Items]
Revenue	66,063	46,615	176,212	140,736
Civil | Water
Disaggregation of Revenue [Line Items]
Revenue	27,098	22,470	70,134	74,080
Civil | Other
Disaggregation of Revenue [Line Items]
Revenue	10,000	23,103	42,200	120,948
Building
Disaggregation of Revenue [Line Items]
Revenue	318,050	360,941	915,639	1,150,834
Building | State and local agencies
Disaggregation of Revenue [Line Items]
Revenue	136,082	99,540	349,245	268,396
Building | Federal agencies
Disaggregation of Revenue [Line Items]
Revenue	42,367	50,437	130,867	150,085
Building | Private owners
Disaggregation of Revenue [Line Items]
Revenue	139,601	210,964	435,527	732,353
Building | Mass transit (includes certain transportation and tunneling projects)
Disaggregation of Revenue [Line Items]
Revenue	40,783	38,868	111,431	99,747
Building | Other
Disaggregation of Revenue [Line Items]
Revenue	20,337	21,068	51,234	76,507
Building | Municipal and government
Disaggregation of Revenue [Line Items]
Revenue	88,624	76,471	248,405	222,855
Building | Commercial and industrial facilities
Disaggregation of Revenue [Line Items]
Revenue	60,711	75,402	149,106	307,414
Building | Health care facilities
Disaggregation of Revenue [Line Items]
Revenue	48,602	20,287	134,439	44,294
Building | Hospitality and gaming
Disaggregation of Revenue [Line Items]
Revenue	17,455	89,317	118,450	276,029
Building | Education facilities
Disaggregation of Revenue [Line Items]
Revenue	41,538	39,528	102,574	123,988
Specialty Contractors
Disaggregation of Revenue [Line Items]
Revenue	251,971	271,063	673,146	877,081
Specialty Contractors | State and local agencies
Disaggregation of Revenue [Line Items]
Revenue	113,907	110,012	297,955	377,016
Specialty Contractors | Federal agencies
Disaggregation of Revenue [Line Items]
Revenue	4,983	14,716	19,503	41,657
Specialty Contractors | Private owners
Disaggregation of Revenue [Line Items]
Revenue	133,081	146,335	355,688	458,408
Specialty Contractors | Mass transit (includes certain transportation and tunneling projects)
Disaggregation of Revenue [Line Items]
Revenue	95,281	135,971	289,703	465,179
Specialty Contractors | Water
Disaggregation of Revenue [Line Items]
Revenue	20,274	29,161	55,693	67,829
Specialty Contractors | Other
Disaggregation of Revenue [Line Items]
Revenue	20,004	25,650	50,560	78,679
Specialty Contractors | Commercial and industrial facilities
Disaggregation of Revenue [Line Items]
Revenue	50,213	33,897	116,514	109,283
Specialty Contractors | Education facilities
Disaggregation of Revenue [Line Items]
Revenue	20,186	13,876	40,627	45,657
Specialty Contractors | Multi-unit residential
Disaggregation of Revenue [Line Items]
Revenue	31,461	28,054	84,642	101,498
Specialty Contractors | Federal government
Disaggregation of Revenue [Line Items]
Revenue	$ 14,552	$ 4,454	$ 35,407	$ 8,956