Revenue (Disaggregation Of Revenue) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Disaggregation of Revenue [Line Items]
Revenue	$ 952,154	$ 1,207,595
State and local agencies
Disaggregation of Revenue [Line Items]
Revenue	529,763	610,007
Federal agencies
Disaggregation of Revenue [Line Items]
Revenue	108,126	123,231
Private owners
Disaggregation of Revenue [Line Items]
Revenue	314,265	474,357
Civil
Disaggregation of Revenue [Line Items]
Revenue	390,795	475,575
Civil | State and local agencies
Disaggregation of Revenue [Line Items]
Revenue	313,842	390,502
Civil | Federal agencies
Disaggregation of Revenue [Line Items]
Revenue	50,694	51,633
Civil | Private owners
Disaggregation of Revenue [Line Items]
Revenue	26,259	33,440
Civil | Mass transit (includes certain transportation and tunneling projects)
Disaggregation of Revenue [Line Items]
Revenue	257,138	308,875
Civil | Military defense facilities
Disaggregation of Revenue [Line Items]
Revenue	49,794	49,536
Civil | Bridges
Disaggregation of Revenue [Line Items]
Revenue	41,247	46,167
Civil | Water
Disaggregation of Revenue [Line Items]
Revenue	20,652	26,810
Civil | Other
Disaggregation of Revenue [Line Items]
Revenue	21,964	44,187
Building
Disaggregation of Revenue [Line Items]
Revenue	330,648	407,233
Building | State and local agencies
Disaggregation of Revenue [Line Items]
Revenue	123,690	76,581
Building | Federal agencies
Disaggregation of Revenue [Line Items]
Revenue	46,098	50,361
Building | Private owners
Disaggregation of Revenue [Line Items]
Revenue	160,860	280,291
Building | Mass transit (includes certain transportation and tunneling projects)
Disaggregation of Revenue [Line Items]
Revenue	60,201	26,535
Building | Other
Disaggregation of Revenue [Line Items]
Revenue	13,068	29,444
Building | Hospitality and gaming
Disaggregation of Revenue [Line Items]
Revenue	76,918	100,567
Building | Municipal and government
Disaggregation of Revenue [Line Items]
Revenue	75,955	71,909
Building | Commercial and industrial facilities
Disaggregation of Revenue [Line Items]
Revenue	39,086	130,052
Building | Health care facilities
Disaggregation of Revenue [Line Items]
Revenue	35,560	10,409
Building | Education facilities
Disaggregation of Revenue [Line Items]
Revenue	29,860	38,317
Specialty Contractors
Disaggregation of Revenue [Line Items]
Revenue	230,711	324,787
Specialty Contractors | State and local agencies
Disaggregation of Revenue [Line Items]
Revenue	92,231	142,924
Specialty Contractors | Federal agencies
Disaggregation of Revenue [Line Items]
Revenue	11,334	21,237
Specialty Contractors | Private owners
Disaggregation of Revenue [Line Items]
Revenue	127,146	160,626
Specialty Contractors | Mass transit (includes certain transportation and tunneling projects)
Disaggregation of Revenue [Line Items]
Revenue	119,027	181,163
Specialty Contractors | Water
Disaggregation of Revenue [Line Items]
Revenue	21,447	21,154
Specialty Contractors | Other
Disaggregation of Revenue [Line Items]
Revenue	23,166	27,570
Specialty Contractors | Commercial and industrial facilities
Disaggregation of Revenue [Line Items]
Revenue	29,857	38,749
Specialty Contractors | Education facilities
Disaggregation of Revenue [Line Items]
Revenue	12,276	13,356
Specialty Contractors | Multi-unit residential
Disaggregation of Revenue [Line Items]
Revenue	$ 24,938	$ 42,795