Fair Value Measurements (Fair Value Measurements within the Fair Value Hierarchy of the Financial Assets) (Details) (USD $) In Thousands, unless otherwise specified	Aug. 31, 2014	Nov. 30, 2013
Contingent consideration [Member] | Total Fair Value [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial liabilities	$ (1,651)	$ (388)
Contingent consideration [Member] | Level 1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial liabilities	0	0
Contingent consideration [Member] | Level 2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial liabilities	0	0
Contingent consideration [Member] | Level 3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial liabilities	(1,651)	(388)
Money market funds [Member] | Total Fair Value [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial assets	69,143	54,513
Money market funds [Member] | Level 1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial assets	69,143	54,513
Money market funds [Member] | Level 2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial assets	0	0
Money market funds [Member] | Level 3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial assets	0	0
State and municipal bond obligations [Member] | Total Fair Value [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial assets	18,912	31,102
State and municipal bond obligations [Member] | Level 1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial assets	0	0
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	18,912	31,102
State and municipal bond obligations [Member] | Level 3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial assets	0	0
Auction rate securities - municipal bonds [Member] | Total Fair Value [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial assets		23,453
Auction rate securities - municipal bonds [Member] | Level 1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial assets		0
Auction rate securities - municipal bonds [Member] | Level 2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial assets		1,520
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		21,933
Auction rate securities - student loans [Member] | Total Fair Value [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial assets		2,828
Auction rate securities - student loans [Member] | Level 1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial assets		0
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		0
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		2,828
Corporate bonds [Member] | Total Fair Value [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial assets		171
Corporate bonds [Member] | Level 1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial assets		0
Corporate bonds [Member] | Level 2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial assets		171
Corporate bonds [Member] | Level 3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial assets		0
Foreign exchange contract [Member] | Total Fair Value [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial assets	(231)
Foreign exchange contract [Member] | Level 1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial assets	0
Foreign exchange contract [Member] | Level 2 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial assets	(231)
Foreign exchange contract [Member] | Level 3 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of financial assets	$ 0