Long-Term Debt - Additional Information (Detail) (USD $)	1 Months Ended		3 Months Ended		9 Months Ended			9 Months Ended		9 Months Ended				1 Months Ended		1 Months Ended		9 Months Ended				9 Months Ended						9 Months Ended
	Nov. 30, 2010	Jun. 30, 2008	Aug. 31, 2011	Aug. 31, 2010	Aug. 31, 2011	Aug. 31, 2010	Feb. 28, 2009	Aug. 31, 2011 5.4 percent Senior Notes	Nov. 30, 2010 5.4 percent Senior Notes	Aug. 31, 2011 5.4 percent Senior Notes Semi Annual Payment, First Payment	Aug. 31, 2011 5.4 percent Senior Notes Semi Annual Payment, Second Payment	Nov. 30, 2010 Senior Notes Due April 2009	Jun. 30, 2008 Senior Notes Due April 2009	Jan. 31, 2011 4.6 percent Senior Notes	Aug. 31, 2011 4.6 percent Senior Notes	Jan. 31, 2011 4.6 percent Senior Notes Semi Annual Payment, First Payment	Jan. 31, 2011 4.6 percent Senior Notes Semi Annual Payment, Second Payment	Aug. 31, 2011 4.8 percent Revenue Bonds	Nov. 30, 2010 4.8 percent Revenue Bonds	Aug. 31, 2011 6.8 percent Revenue Bonds	Nov. 30, 2010 6.8 percent Revenue Bonds	Aug. 31, 2011 6.8 percent Revenue Bonds Interest Payments	Aug. 31, 2011 6.8 percent Revenue Bonds Principal Payments	Aug. 31, 2011 6.3 percent Term Loan Year	Nov. 30, 2010 6.3 percent Term Loan	Aug. 31, 2011 TIF bond debt service funding commitment	Nov. 30, 2010 TIF bond debt service funding commitment	Aug. 31, 2011 TIF bond debt service funding commitment Semi Annual Payment, First Payment	Aug. 31, 2011 TIF bond debt service funding commitment Semi Annual Payment, Second Payment	Aug. 31, 2011 TIF bond debt service funding commitment Interest Payments	Aug. 31, 2011 TIF bond debt service funding commitment Principal Payments	Aug. 31, 2011 TIF bond debt service funding commitment Term Bond Due December 1st 2017	Aug. 31, 2011 TIF bond debt service funding commitment Term Bond Due December 1st 2027	Nov. 30, 2010 LIBOR Minimum	Nov. 30, 2010 LIBOR Maximum
Debt Disclosure [Line Items]
Debt term																								25
Proceeds from long-term debt					$ 65,000,000									$ 65,000,000
Debt issuance amount													150,000,000
Debt outstanding amount												65,000,000
Debt, due date								2014-04					2009-04	2021-01										2034-10
Debt, interest rate								5.40%	5.40%					4.60%	4.60%			4.80%	4.80%	6.80%	6.80%			6.30%	6.30%							6.20%	6.80%
Debt, monthly payment																		29,000						292,000
Frequency of periodic payment								semi-annual						semi-annual								Semi-annual	Annually							Semi-annual	October 1 of each year
Long-term debt	306,290,000		287,740,000		287,740,000			87,023,000	87,018,000						65,000,000			1,356,000	1,541,000		1,180,000			50,750,000	50,994,000	63,611,000	63,557,000					14,600,000	49,700,000
Debt, maturity date																																Dec. 01, 2017	Dec. 01, 2027
Interest payment date										April 15	October 15					January 18	July 18											April 1	October 1
Notional amount of interest rate swap agreement		150,000,000
Reason for entering into/discontinuation of interest rate swap		To effectively lock in a substantial portion of the interest rate exposure on approximately $150.0 million notional amount in anticipation of refinancing the $150.0 million of senior notes that matured in April 2009				Reduction in the anticipated debt issuance from $150.0 million to $65.0 million
Interest rate swap expiration							2011-02
Interest rate swap expense				(14,081,000)		(16,587,000)
Deferred in other comprehensive loss associated with interest rate swap being amortized as interest expense over life of the private placement completed in January 2011			6,100,000		6,100,000
Interest rate swap expense expected to be recognized during the next 12 months			(1,100,000)		(1,100,000)
2010 Credit Facility	November 2010
2010 Credit Facility current borrowing capacity	300,000,000
2010 Credit Facility potential borrowing capacity	500,000,000
Termination of revolving credit facility	November 2010				November 2015
2010 Credit Facility interest rate description					Accrues interest at LIBOR plus 150.0-225.0 basis points, depending on the better of the Company's debt rating as determined by specified rating agencies or the Company's leverage ratio
2010 Credit Facility amount outstanding			20,000,000		20,000,000
Debt instrument basis points																																		1.50%	2.25%
Interest expense			3,751,000	3,533,000	11,432,000	11,782,000
Interest capitalized			900,000	700,000	1,900,000	1,500,000
Financing costs deferred	$ 5,100,000		$ 5,000,000		$ 5,000,000