Revenue (Schedule Of Revenue By Contract Type) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Disaggregation of Revenue [Line Items]
Revenue	$ 776,300	$ 952,154
Fixed price
Disaggregation of Revenue [Line Items]
Revenue	573,644	638,574
Guaranteed maximum price
Disaggregation of Revenue [Line Items]
Revenue	71,596	177,135
Unit price
Disaggregation of Revenue [Line Items]
Revenue	57,076	65,365
Cost plus fee and other
Disaggregation of Revenue [Line Items]
Revenue	73,984	71,080
Civil
Disaggregation of Revenue [Line Items]
Revenue	349,870	390,795
Civil | Fixed price
Disaggregation of Revenue [Line Items]
Revenue	311,373	336,993
Civil | Guaranteed maximum price
Disaggregation of Revenue [Line Items]
Revenue	62	293
Civil | Unit price
Disaggregation of Revenue [Line Items]
Revenue	33,012	50,510
Civil | Cost plus fee and other
Disaggregation of Revenue [Line Items]
Revenue	5,423	2,999
Building
Disaggregation of Revenue [Line Items]
Revenue	229,653	330,648
Building | Fixed price
Disaggregation of Revenue [Line Items]
Revenue	96,116	102,518
Building | Guaranteed maximum price
Disaggregation of Revenue [Line Items]
Revenue	69,778	171,509
Building | Unit price
Disaggregation of Revenue [Line Items]
Revenue	0	33
Building | Cost plus fee and other
Disaggregation of Revenue [Line Items]
Revenue	63,759	56,588
Specialty Contractors
Disaggregation of Revenue [Line Items]
Revenue	196,777	230,711
Specialty Contractors | Fixed price
Disaggregation of Revenue [Line Items]
Revenue	166,155	199,063
Specialty Contractors | Guaranteed maximum price
Disaggregation of Revenue [Line Items]
Revenue	1,756	5,333
Specialty Contractors | Unit price
Disaggregation of Revenue [Line Items]
Revenue	24,064	14,822
Specialty Contractors | Cost plus fee and other
Disaggregation of Revenue [Line Items]
Revenue	$ 4,802	$ 11,493