Notes Payable (Narratives) (Details) - USD ($)			3 Months Ended		9 Months Ended
	Jun. 16, 2015	Feb. 17, 2015	Aug. 31, 2015	Aug. 31, 2014	Aug. 31, 2015	Aug. 31, 2014	May. 31, 2015	Nov. 30, 2014
Debt Instrument [Line Items]
Line of Credit Facility, Current Borrowing Capacity			$ 275,000,000		$ 275,000,000		$ 200,000,000
Letters of credit outstanding			$ 26,400,000		26,400,000			$ 26,700,000
Proceeds from Issuance of Senior Long-term Debt					$ 250,000,000	$ 400,000,000
Incremental Common Shares Attributable to Dilutive Effect of Conversion of Debt Securities			8,402,000	8,402,000	8,402,000	8,402,000
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months			$ 15,800,000		$ 15,800,000
Long-term Debt, Maturities, Repayments of Principal in Year Two			25,400,000		25,400,000
Long-term Debt, Maturities, Repayments of Principal in Year Three			265,000,000		265,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Four			300,000,000		300,000,000
Long-term Debt, Maturities, Repayments of Principal in Year Five			630,000,000		630,000,000
Long-term Debt, Maturities, Repayments of Principal after Year Five			1,400,000,000		1,400,000,000
Repayments of Senior Debt					199,906,000	$ 0
Inventories pledged to collateralize mortgages and land contracts, carrying value			145,000,000		145,000,000
Letter of Credit [Member]
Debt Instrument [Line Items]
Unsecured revolving credit facility, maximum borrowing capacity			137,500,000		137,500,000
Line of Credit Facility, Amount Outstanding			1,699,000.000		1,699,000.000
Letters of credit outstanding			24,700,000		24,700,000			$ 26,700,000
Unsecured revolving credit facility, remaining borrowing capacity			135,800,000		$ 135,800,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Unsecured revolving credit facility, expiration date					Aug. 07, 2019
Unsecured revolving credit facility, maximum borrowing capacity			450,000,000		$ 450,000,000
Line of Credit Facility, Amount Outstanding			0		0
Unsecured revolving credit facility, remaining borrowing capacity			$ 273,300,000		$ 273,300,000
Revolving Credit Facility [Member] | Minimum [Member]
Debt Instrument [Line Items]
Line of credit facility, unused capacity, commitment fee percentage					0.30%
Revolving Credit Facility [Member] | Maximum [Member]
Debt Instrument [Line Items]
Line of credit facility, unused capacity, commitment fee percentage					0.50%
Convertible Senior Notes Due Two Thousand Nineteen At One Point Three Seven Five Percent [Member] [Member]
Debt Instrument [Line Items]
Senior notes, rate			1.375%		1.375%
Convertible Notes Payable [Member] | Convertible Senior Notes Due Two Thousand Nineteen At One Point Three Seven Five Percent [Member] [Member]
Debt Instrument [Line Items]
Senior notes, rate			1.375%		1.375%			1.375%
Debt Conversion, Converted Instrument, Shares Issued					36.5297
Debt instrument, convertible, conversion price			$ 27.37		$ 27.37
Incremental Common Shares Attributable to Dilutive Effect of Conversion of Debt Securities					8,401,831
Senior Notes [Member] | Senior Notes Due Two Thousand Fifteen at Six Point Two Five Percent [Member]
Debt Instrument [Line Items]
Senior notes, rate								6.25%
Repayments of Senior Debt	$ 199,900,000
Senior Notes [Member] | Senior notes due September 15, 2017 at 9.10%
Debt Instrument [Line Items]
Senior notes, rate			9.10%		9.10%			9.10%
Senior Notes [Member] | Senior Notes Due Two Thousand Nineteen at Four Point Seven Five Percent [Member]
Debt Instrument [Line Items]
Senior notes, rate			4.75%		4.75%			4.75%
Senior Notes [Member] | Senior notes due March 15, 2020 at 8.00%
Debt Instrument [Line Items]
Senior notes, rate			8.00%		8.00%			8.00%
Senior Notes [Member] | Senior notes due September 15, 2022 at 7.50%
Debt Instrument [Line Items]
Senior notes, rate			7.50%		7.50%			7.50%
Senior Notes [Member] | Senior Notes Due Two Thousand Twenty Three At Seven Point Six Two Five Percent [Domain]
Debt Instrument [Line Items]
Debt Instrument, Face Amount		$ 250,000,000
Proceeds from Issuance of Senior Long-term Debt		$ 247,000,000
Senior notes, rate			7.625%		7.625%