Consolidated Statements of Shareholders' Equity (Deficit) - USD ($) shares in Millions, $ in Millions	Total	Common Stock [Member]	Other Capital [Member]	Treasury Stock [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Loss [Member]
Beginning balance at Nov. 30, 2013	$ 37.3	$ 5.9	$ 280.3	$ 0.0	$ (20.6)	$ (228.3)
Beginning balance (in shares) at Nov. 30, 2013		59.9
Net income (loss)	(50.0)				(50.0)
Amortization of net actuarial losses, net of income taxes	31.1					31.1
Actuarial losses arising during the period, net of income taxes	(136.0)					(136.0)
Amortization of prior service credits, net of income taxes	(0.5)					(0.5)
Reclassification of redeemable common stock	(1.4)		(1.4)
Reclassification from redeemable common stock (in shares)		0.1
Tax benefit from shares issued under equity plans	1.3		1.3
Repurchase of shares to satisfy tax withholding obligations	(64.5)			(64.5)
Repurchase of shares to satisfy tax withholding obligations (in shares)		(3.5)
Stock-based compensation and shares issued under equity plans, net	7.2		7.2
Stock-based compensation and other, net (in shares)		0.4
Ending balance at Nov. 30, 2014	(175.5)	$ 5.9	287.4	(64.5)	(70.6)	(333.7)
Ending balance, (in shares) at Nov. 30, 2014		56.9
Net income (loss)	(16.2)				(16.2)
Amortization of net actuarial losses, net of income taxes	49.4					49.4
Actuarial losses arising during the period, net of income taxes	(56.6)					(56.6)
Amortization of prior service credits, net of income taxes	(0.8)					(0.8)
Reclassification of redeemable common stock	0.7		0.7
Reclassification from redeemable common stock (in shares)		(0.1)
Tax benefit from shares issued under equity plans	2.5		2.5
Conversion of debt to common stock	49.0	$ 0.5	48.5
Conversion of debt to common stock (in shares)		5.5
Repurchase of shares for option cost and to satisfy tax withholding obligations	(6.7)		(6.7)
Repurchase of shares to satisfy tax withholding obligations (in shares)		(0.3)
Stock-based compensation and shares issued under equity plans, net	7.8	$ 0.1	7.7
Stock-based compensation and other, net (in shares)		0.9
Ending balance at Nov. 30, 2015	(146.4)	$ 6.5	340.1	(64.5)	(86.8)	(341.7)
Ending balance, (in shares) at Nov. 30, 2015		62.9
Beginning balance at Nov. 30, 2014	(175.5)	$ 5.9	287.4	(64.5)	(70.6)	(333.7)
Beginning balance (in shares) at Nov. 30, 2014		56.9
Ending balance at Dec. 31, 2015	(142.2)	$ 6.5	342.6	(64.5)	(79.8)	(347.0)
Ending balance, (in shares) at Dec. 31, 2015		62.9
Beginning balance at Nov. 30, 2015	(146.4)	$ 6.5	340.1	(64.5)	(86.8)	(341.7)
Beginning balance (in shares) at Nov. 30, 2015		62.9
Net income (loss)	7.0				7.0
Amortization of net actuarial losses, net of income taxes	3.4
Actuarial losses arising during the period, net of income taxes	(8.6)					(8.6)
Amortization of actuarial losses and prior service credits, net of income taxes	3.3					3.3
Amortization of prior service credits, net of income taxes	(0.1)
Reclassification of redeemable common stock	(0.7)		(0.7)
Tax benefit from shares issued under equity plans	2.4		2.4
Repurchase of shares for option cost and to satisfy tax withholding obligations	(0.2)		(0.2)
Stock-based compensation and shares issued under equity plans, net	1.0		1.0
Ending balance at Dec. 31, 2015	(142.2)	$ 6.5	342.6	(64.5)	(79.8)	(347.0)
Ending balance, (in shares) at Dec. 31, 2015		62.9
Net income (loss)	18.0				18.0
Amortization of net actuarial losses, net of income taxes	37.1					37.1
Actuarial losses arising during the period, net of income taxes	7.5					7.5
Amortization of prior service credits, net of income taxes	(0.6)					(0.6)
Reclassification of redeemable common stock	0.5		0.5
Tax benefit from shares issued under equity plans	0.3		0.3
Equity component of convertible debt	54.5		54.5
Conversion of debt to common stock	49.0	$ 0.4	48.6
Conversion of debt to common stock (in shares)		5.4
Repurchase of shares to satisfy tax withholding obligations		$ (64.5)
Repurchase of shares to satisfy tax withholding obligations (in shares)		(3.5)
Repurchase of shares for option cost and to satisfy tax withholding obligations	(3.9)		(3.9)
Repurchase of shares to satisfy tax withholding obligations (in shares)		(0.3)
Stock-based compensation and shares issued under equity plans, net	14.3		14.3
Stock-based compensation and other, net (in shares)		1.2
Ending balance at Dec. 31, 2016	$ 34.5	$ 6.9	$ 456.9	$ (64.5)	$ (61.8)	$ (303.0)
Ending balance, (in shares) at Dec. 31, 2016		69.2