Accounts Receivable, Net of Allowance (Tables)

12 Months Ended

Dec. 31, 2012

Accounts, Notes, Loans and Financing Receivable [Line Items]

Schedule Of Accounts Receivable And Allowance For Doubtful Accounts

Accounts receivable, net of allowance, which is classified as current, is composed of the following as of the dates indicated (in millions):

	December 31,
	2012			2011
Contract billings	$	522.0		$	395.7
Retainage	113.5			41.7
Costs and earnings in excess of billings	252.8			228.7
Accounts receivable, gross	$	888.3		$	666.1
Less allowance for doubtful accounts	(11.2		)	(7.6		)
Accounts receivable, net	$	877.1		$	658.5

Allowance for Doubtful Accounts [Member]

Accounts, Notes, Loans and Financing Receivable [Line Items]

Schedule Of Accounts Receivable And Allowance For Doubtful Accounts

	Years Ended December 31,
	2012			2011
Allowance for doubtful accounts at beginning of year	$	7.6		$	8.3
Provision for doubtful accounts	6.9			2.0
Amounts charged against the allowance	(3.3		)	(2.7		)
Allowance for doubtful accounts at end of year	$	11.2		$	7.6