Revenue (Schedule Of Revenue By Contract Type) (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
Fixed price
Disaggregation of Revenue [Line Items]
Revenue	726,906	798,641	1,925,226	2,398,421
Guaranteed maximum price
Disaggregation of Revenue [Line Items]
Revenue	150,445	225,317	477,196	748,634
Unit price
Disaggregation of Revenue [Line Items]
Revenue	116,323	95,117	275,962	291,913
Cost plus fee and other
Disaggregation of Revenue [Line Items]
Revenue	77,252	59,147	205,723	166,092
Civil
Disaggregation of Revenue [Line Items]
Revenue	500,905	546,218	1,295,322	1,577,145
Civil | Fixed price
Disaggregation of Revenue [Line Items]
Revenue	416,216	473,212	1,090,623	1,353,436
Civil | Guaranteed maximum price
Disaggregation of Revenue [Line Items]
Revenue	(13)	502	581	2,270
Civil | Unit price
Disaggregation of Revenue [Line Items]
Revenue	90,372	71,429	213,092	212,678
Civil | Cost plus fee and other
Disaggregation of Revenue [Line Items]
Revenue	(5,670)	1,075	(8,974)	8,761
Building
Disaggregation of Revenue [Line Items]
Revenue	318,050	360,941	915,639	1,150,834
Building | Fixed price
Disaggregation of Revenue [Line Items]
Revenue	103,804	89,895	270,618	269,693
Building | Guaranteed maximum price
Disaggregation of Revenue [Line Items]
Revenue	144,831	219,395	462,294	737,251
Building | Unit price
Disaggregation of Revenue [Line Items]
Revenue	0	130	33	(1,323)
Building | Cost plus fee and other
Disaggregation of Revenue [Line Items]
Revenue	69,415	51,521	182,694	145,213
Specialty Contractors
Disaggregation of Revenue [Line Items]
Revenue	251,971	271,063	673,146	877,081
Specialty Contractors | Fixed price
Disaggregation of Revenue [Line Items]
Revenue	206,886	235,534	563,985	775,292
Specialty Contractors | Guaranteed maximum price
Disaggregation of Revenue [Line Items]
Revenue	5,627	5,420	14,321	9,113
Specialty Contractors | Unit price
Disaggregation of Revenue [Line Items]
Revenue	25,951	23,558	62,837	80,558
Specialty Contractors | Cost plus fee and other
Disaggregation of Revenue [Line Items]
Revenue	$ 13,507	$ 6,551	$ 32,003	$ 12,118