Business Segments (Total Assets For Reportable Segments) (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Segment Reporting Information [Line Items]
Assets	$ 4,760,974	$ 4,724,898
Corporate and other
Segment Reporting Information [Line Items]
Assets	(290,023)	(198,449)
Civil | Operating Segments
Segment Reporting Information [Line Items]
Assets	3,467,173	3,310,648
Building | Operating Segments
Segment Reporting Information [Line Items]
Assets	976,400	980,989
Specialty Contractors | Operating Segments
Segment Reporting Information [Line Items]
Assets	$ 607,424	$ 631,710