Line of Credit - Additional Information (Detail) (USD $)	1 Months Ended	3 Months Ended								3 Months Ended			12 Months Ended	1 Months Ended
	Dec. 11, 2013	Jan. 31, 2014	Oct. 31, 2013	Nov. 30, 2010	Jan. 31, 2014 Standby Letters of Credit	Nov. 30, 2010 Standby Letters of Credit	Nov. 30, 2010 Swing Line Loan	Jan. 31, 2014 Maximum	Jan. 31, 2014 Interest Rate Swap Agreements	Jan. 31, 2014 Interest Rate Swap Agreements Minimum	Jan. 31, 2014 Interest Rate Swap Agreements Maximum	Jan. 31, 2014 Forward starting swaps	Oct. 31, 2011 Second Amendment	Nov. 30, 2010 Second Amendment Minimum	Nov. 30, 2010 Second Amendment Maximum	Nov. 30, 2010 Second Amendment Federal Funds Rate	Nov. 30, 2010 Second Amendment One Month Eurodollar Rate	Nov. 30, 2010 Second Amendment Base Rate Minimum	Nov. 30, 2010 Second Amendment Base Rate Maximum	Nov. 30, 2010 Second Amendment Eurodollar Minimum	Nov. 30, 2010 Second Amendment Eurodollar Maximum
Line of Credit Facility [Line Items]
Line of credit, maximum borrowing capacity	$ 800,000,000		$ 650,000,000.0	$ 650,000,000.0	$ 300,000,000	$ 300,000,000.0	$ 50,000,000.0	$ 1,000,000,000
Syndicated line of credit facility, expiration date													Sep. 08, 2016
Line of credit facility, unused portion, commitment fee percentage, increase (decrease) in percentage	0.025%
Variable rate																0.50%	1.00%	0.00%	0.75%	1.00%	1.75%
Percentage of commitment fee on the unused portion of the Facility														0.20%	0.275%
Covenants maximum 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%
Line of credit, amount outstanding		367,000,000	314,900,000
Standby letters of credit under the credit facility		105,600,000	100,600,000
Line of credit, borrowing capacity currently available		327,400,000	234,500,000
Derivative, effective date										Mar. 18, 2013	Apr. 11, 2013	Feb. 24, 2011
Notional amount									$ 155,000,000			$ 25,000,000
Derivative, fixed interest rate										0.44%	0.47%	0.89%
Derivative, maturity date										Mar. 18, 2016	Apr. 11, 2016	Feb. 24, 2014
Derivative agreement date												Oct. 19, 2010
Interest rate swap agreement period												3 years