Accounts Receivable, Net Of Allowance (Schedule Of Accounts Receivable) (Detail) (USD $)	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Receivables [Abstract]
Contract billings	$ 522,000,000	$ 395,700,000
Retainage	113,500,000	41,700,000
Costs and earnings in excess of billings	252,800,000	228,700,000
Accounts receivable, gross	888,300,000	666,100,000
Less allowance for doubtful accounts	(11,200,000)	(7,600,000)	(8,300,000)
Accounts receivable, net	$ 877,131,000	$ 658,528,000