Stockholders' Equity (Details) - USD ($) $ in Thousands	3 Months Ended
	Feb. 28, 2018	Feb. 28, 2017
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ 1,926,311
Net loss	(71,255)	$ 14,259
Dividends on common stock	$ (2,322)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period (in shares)	268,954
Stock Issued During Period, Value, Stock Options Exercised	$ 2,946
Stock Issued During Period, Value, Share-based Compensation, Gross	0
Stock-based compensation	3,829
Stock repurchases	(6,787)
Ending balance	$ 1,852,722
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Shares, Outstanding (in shares)	(117,946,000)
Beginning balance	$ 117,946
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period (in shares)	268,000
Stock Issued During Period, Value, Stock Options Exercised	$ 268
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures (in shares)	0
Stock Issued During Period, Value, Share-based Compensation, Gross	$ 0
Common Stock, Shares, Outstanding (in shares)	(118,214,000)
Ending balance	$ 118,214
Paid-in Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	727,483
Stock Issued During Period, Value, Stock Options Exercised	2,678
Stock Issued During Period, Value, Share-based Compensation, Gross	(4,551)
Stock-based compensation	3,829
Ending balance	729,439
Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	1,735,695
Net loss	(71,255)
Dividends on common stock	(2,322)
Ending balance	1,662,118
Accumulated Other Comprehensive Income
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(16,924)
Ending balance	$ (16,924)
Grantor Stock Ownership Trust
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Shares, Outstanding (in shares)	(8,898,000)
Beginning balance	$ (96,509)
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures (in shares)	(438,000)
Stock Issued During Period, Value, Share-based Compensation, Gross	$ 4,749
Common Stock, Shares, Outstanding (in shares)	(8,460,000)
Ending balance	$ (91,760)
Treasury Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Shares, Outstanding (in shares)	(22,021,000)
Beginning balance	$ (541,380)
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures (in shares)	(10,000)
Stock Issued During Period, Value, Share-based Compensation, Gross	$ (198)
Stock repurchases	$ (6,787)
Treasury Stock, Shares, Acquired (in shares)	(217,000)
Common Stock, Shares, Outstanding (in shares)	(22,248,000)
Ending balance	$ (548,365)