Term Loan and Line of Credit (Narrative) (Details) - USD ($)		3 Months Ended		6 Months Ended
	Dec. 02, 2014	May. 31, 2015	May. 31, 2014	May. 31, 2015	May. 31, 2014
Line of Credit Facility [Line Items]
Unamortized debt issuance costs	$ 300,000
Amortization of debt issuance costs			$ 100,000		$ 100,000
Letter of credit [Member]
Line of Credit Facility [Line Items]
Line of credit facility outstanding amount	700,000
Credit Agreement [Member]
Line of Credit Facility [Line Items]
Term loan	150,000,000
Unsecured credit facility	150,000,000
Additional borrowing capacity available	75,000,000
Interest rate during period (as a percent)				1.94%
Principal payments for years one and two		$ 1,900,000		$ 1,900,000
Principal payments for years three and four		3,800,000		3,800,000
Principal payments for years five and thereafter		5,600,000		5,600,000
Fair value of term loan		146,300,000		146,300,000
Due in next 12 months		7,500,000		7,500,000
Debt issuance cost				1,700,000
Amortization of debt issuance costs		100,000		$ 200,000
Percent of domestic subsidiary capital stock guaranteeing debt				100.00%
Percent of foreign subsidiary capital stock guaranteeing debt				65.00%
Credit Agreement [Member] | Letter of credit [Member]
Line of Credit Facility [Line Items]
Unsecured credit facility	25,000,000.0
Line of credit facility outstanding amount		$ 500,000		$ 500,000
Credit Agreement [Member] | Swing line loans [Member]
Line of Credit Facility [Line Items]
Unsecured credit facility	$ 25,000,000.0
Minimum [Member] | Credit Agreement [Member]
Line of Credit Facility [Line Items]
Commitment fee percentage	0.25%
Minimum [Member] | Eurodollar [Member] | Credit Agreement [Member]
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.50%
Minimum [Member] | Base Rate [Member] | Credit Agreement [Member]
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.50%
Maximum [Member] | Credit Agreement [Member]
Line of Credit Facility [Line Items]
Commitment fee percentage	0.40%
Maximum [Member] | Eurodollar [Member] | Credit Agreement [Member]
Line of Credit Facility [Line Items]
Basis spread on variable rate	2.25%
Maximum [Member] | Base Rate [Member] | Credit Agreement [Member]
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.25%