Consolidated Statements of Comprehensive Income Statement - USD ($) $ in Thousands	12 Months Ended
	Nov. 30, 2017	Nov. 30, 2016	Nov. 30, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 180,595	$ 105,615	$ 84,643
Net actuarial gain (loss) arising during the period	(3,143)	468	3,745
Amortization of net actuarial loss	142	79	848
Amortization of prior service cost	1,556	1,556	1,556
Other comprehensive income (loss) before tax	(1,445)	2,103	6,149
Income tax benefit (expense) related to items of other comprehensive income (loss)	578	(841)	(2,460)
Other comprehensive income (loss), net of tax	(867)	1,262	3,689
Comprehensive income	$ 179,728	$ 106,877	$ 88,332