Restructuring Charges (Narrative) (Details) - USD ($)	3 Months Ended			9 Months Ended
	Aug. 31, 2017	Feb. 28, 2017	Aug. 31, 2016	Aug. 31, 2017	Aug. 31, 2016	Nov. 30, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring expenses	$ 923,000		$ (36,000)	$ 18,724,000	$ 229,000
Restructuring reserve	3,000,000			3,000,000		$ 1,550,000
2017 Restructuring Activities [Member]
Restructuring Cost and Reserve [Line Items]
Global workforce reduction (as a percent)		20.00%
Restructuring expenses	900,000			18,632,000
Restructuring reserve	2,671,000			2,671,000		0
2017 Restructuring Activities [Member] | Other accrued liabilities [Member]
Restructuring Cost and Reserve [Line Items]
Short-term portion of restructuring reserve	2,400,000			2,400,000
2017 Restructuring Activities [Member] | Other Noncurrent Liabilities [Member]
Restructuring Cost and Reserve [Line Items]
Long-term portion of restructuring reserve	300,000			300,000
2016 Restructuring Activities [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expenses	0			0
Restructuring reserve	$ 301,000			$ 301,000		$ 1,415,000