Commitments and Contingencies - Additional Information (Detail) (USD $)				1 Months Ended			1 Months Ended
	Jan. 31, 2014	Oct. 31, 2013	Jan. 31, 2014 Effective date starting after January 31, 2014	Jul. 31, 2012 Augustus Claim	Feb. 08, 2012 Augustus	Jan. 31, 2014 Augustus	Jan. 14, 2013 Augustus Motion against others	Jul. 31, 2012 Augustus Motion against others	Apr. 11, 2013 Bojorquez	May 17, 2012 Bojorquez
Loss Contingencies [Line Items]
Surety bonds	$ 362,800,000		$ 12,700,000
Total letters of credit	105,600,000	100,600,000
Guarantee obligation	33,700,000	31,400,000
Loss contingency amount accrued for probable losses	2,300,000
Amount of reasonably possible losses, Minimum	1,000,000
Amount of reasonably possible losses, Maximum	98,100,000
Loss Contingency, estimate of possible loss						94,200,000
Damages sought amount					103,100,000		4,500,000	12,400,000
Payment awarded to plaintiffs				$ 89,700,000					$ 2,500,000	$ 800,000
Number of claim suit filed				3