Fair Value Measurements (Fair Value Measurements Within The Fair Value Hierarchy Of The Financial Assets) (Details) (USD $) In Thousands, unless otherwise specified	May 31, 2012	Nov. 30, 2011
Money Market Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial assets	$ 29,832	$ 24,220
Money Market Funds [Member] | Level 1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial assets	29,832	24,220
State And Municipal Bond Obligations [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial assets	78,215	84,398
State And Municipal Bond Obligations [Member] | Level 2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial assets	78,215	84,398
Brazilian Mutual Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial assets		15,346
Brazilian Mutual Funds [Member] | Level 1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial assets		15,346
Auction Rate Securities - Municipal Bonds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial assets	23,371	22,931
Auction Rate Securities - Municipal Bonds [Member] | Level 3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial assets	23,371	22,931
Auction Rate Securities - Student Loans [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial assets	10,777	10,608
Auction Rate Securities - Student Loans [Member] | Level 2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial assets	2,700
Auction Rate Securities - Student Loans [Member] | Level 3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial assets	8,077	10,608
Corporate Bonds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial assets	6,449	2,562
Corporate Bonds [Member] | Level 2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial assets	6,449	2,562
Foreign Exchange Derivatives [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial assets	(172)	52
Foreign Exchange Derivatives [Member] | Level 2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial assets	$ (172)	$ 52