Line of Credit - Additional Information (Detail)		6 Months Ended	12 Months Ended
		Apr. 30, 2016 USD ($) instrument	Oct. 31, 2015 USD ($)	May. 31, 2016 USD ($)
Line of Credit Facility
Syndicated line of credit, increased capacity		$ 800,000,000
Line of credit, maximum borrowing capacity		$ 1,000,000,000
Debt covenant leverage ratio		3.25
Minimum fixed charge coverage ratio		1.50
Consolidated net worth		$ 570,000,000
Consolidated net income earned		50.00%
Aggregate increases in stockholders' equity		100.00%
Covenants maximum leverage ratio		3.50
Standby letters of credit		$ 127,600,000	$ 112,900,000
Line of credit, borrowing capacity currently available	[1]	463,500,000	529,100,000
Accumulated other comprehensive income (loss), cumulative changes in net gain (loss) from cash flow hedges, effect net of tax		(100,000)	$ 100,000
Interest Rate Swap
Line of Credit Facility
Notional amount		$ 155,000,000
Derivative, Number of Instruments Held | instrument		3
Derivative, fixed interest rate		1.05%
Minimum
Line of Credit Facility
Percentage of commitment fee on the unused portion of the Facility		0.20%
Maximum
Line of Credit Facility
Percentage of commitment fee on the unused portion of the Facility		0.275%
Base Rate | Minimum
Line of Credit Facility
Variable rate		0.00%
Base Rate | Maximum
Line of Credit Facility
Variable rate		0.75%
Eurodollar
Line of Credit Facility
Variable rate		1.00%
Eurodollar | Minimum
Line of Credit Facility
Variable rate		1.00%
Eurodollar | Maximum
Line of Credit Facility
Variable rate		1.75%
Federal Funds Rate
Line of Credit Facility
Variable rate		0.50%
Swing Line Loan
Line of Credit Facility
Line of credit, maximum borrowing capacity		$ 50,000,000
Standby Letters of Credit
Line of Credit Facility
Line of credit, maximum borrowing capacity		$ 300,000,000
Subsequent Event | Interest Rate Swap
Line of Credit Facility
Notional amount				$ 105,000,000

[1] Availability of our borrowing capacity is subject to, and limited by, compliance with the covenants described above.