Revisions in Estimates (Tables)

6 Months Ended

Jun. 30, 2018

Construction Segment [Member]

Change In Accounting Estimate [Line Items]

Schedule of Projects Summarized

The projects are summarized as follows:

Increases

		Three Months Ended June 30,						Six Months Ended June 30,
(dollars in millions)		2018			2017			2018			2017
Number of projects with upward estimate changes			1			—			2			—
Range of increase in gross profit from each project, net	$		1.4	$		—	$	1.4 - 1.4		$		—
Increase on project profitability	$		1.4	$		—	$		2.8	$		—

Decreases

		Three Months Ended June 30,						Six Months Ended June 30,
(dollars in millions)		2018			2017			2018			2017
Number of projects with downward estimate changes			3			1			3			1
Range of reduction in gross profit from each project, net	$	1.2 - 2.5		$		1.1	$	1.3 - 2.6		$		1.8
Decrease on project profitability	$		5.9	$		1.1	$		6.1	$		1.8

Large Project Construction [Member]

Change In Accounting Estimate [Line Items]

Schedule of Projects Summarized

The projects are summarized as follows:

Increases

		Three Months Ended June 30,						Six Months Ended June 30,
(dollars in millions)		2018			2017			2018			2017
Number of projects with upward estimate changes			1			—			1			—
Range of increase in gross profit from each project, net	$		1.0	$		—	$		1.2	$		—
Increase on project profitability	$		1.0	$		—	$		1.2	$		—

Decreases

		Three Months Ended June 30,						Six Months Ended June 30,
(dollars in millions)		2018			2017			2018			2017
Number of projects with downward estimate changes			3			5			5			7
Range of reduction in gross profit from each project, net	$	1.0 - 15.7		$	1.1 - 8.1		$	1.1 - 18.3		$	1.0 - 10.8
Decrease on project profitability	$		31.3	$		23.8	$		41.0	$		37.8