Selected Unaudited Quarterly Financial Information (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Dec. 31, 2012	Sep. 30, 2011 Middle East	Jun. 30, 2011 Middle East
Quarterly Financial Information [Line Items]
Decline in operating income		$ 75.4	$ 49.1
Project charges	$ 52.0	$ 50.0