Income Taxes (Details) - USD ($)		3 Months Ended		9 Months Ended
		Aug. 31, 2017	Aug. 31, 2016	Aug. 31, 2017	Aug. 31, 2016	Nov. 30, 2016
Income Tax Expense (Benefit), Continuing Operations [Abstract]
Income tax expense	[1]	$ (29,000,000)	$ (14,100,000)	$ (56,400,000)	$ (26,200,000)
Effective Income Tax Rate Reconciliation, Percent	[1]	36.60%	26.40%	36.90%	27.80%
Income Tax Credits and Adjustments		$ 2,600,000	$ 6,700,000	$ 3,800,000	$ 10,400,000
Unrecognized Tax Benefits		100,000		100,000		$ 100,000
Net (increase) reduction in valuation allowance		(200,000.0)
Valuation Allowances and Reserves, Additions for Adjustments				0
Valuation allowance		24,600,000		24,600,000		24,800,000
Income Tax Contingency [Line Items]
Deferred Tax Assets, Gross		707,700,000		707,700,000		$ 763,800,000
Minimum [Member]
Income Tax Contingency [Line Items]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit		0		0
Maximum [Member]
Income Tax Contingency [Line Items]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit		$ 100,000		$ 100,000

[1] (a) Amounts reflect the favorable net impact of federal energy tax credits we earned from building energy-efficient homes through December 31, 2016. The net impact of these tax credits was $2.6 million and $6.7 million for the three months ended August 31, 2017 and 2016, respectively, and $3.8 million and $10.4 million for the nine months ended August 31, 2017 and 2016, respectively.