Long-Term Debt And Credit Facilities (Details) (USD $)	0 Months Ended	1 Months Ended	12 Months Ended				12 Months Ended		0 Months Ended	1 Months Ended		0 Months Ended		12 Months Ended								12 Months Ended									12 Months Ended			12 Months Ended				12 Months Ended
	Dec. 19, 2011 months	Jun. 30, 2003 years	Nov. 30, 2011 years months	Nov. 30, 2009	Nov. 30, 2010	May 31, 2007	Nov. 30, 2011 Mortgage Note [Member] years	Nov. 30, 2009 Unsecured Debt [Member]	Dec. 19, 2011 Cash Borrowings [Member]	Dec. 31, 2011 Cash Borrowings [Member]	Nov. 30, 2011 Cash Borrowings [Member]	Dec. 19, 2011 Credit Agreement [Member]	Nov. 30, 2011 Credit Agreement [Member]	Nov. 30, 2011 Letters Of Credit [Member] years	Dec. 19, 2011 Letters Of Credit [Member]	Dec. 19, 2011 Swing Line Loans [Member]	Nov. 30, 2011 Swing Line Loans [Member]	Dec. 31, 2011 Revolving Line Of Credit [Member]	Nov. 30, 2011 Revolving Line Of Credit [Member]	Dec. 31, 2011 Letters Of Credit One [Member]	Nov. 30, 2011 Letters Of Credit One [Member]	Nov. 30, 2011 Letters Of Credit Two [Member]	Dec. 31, 2011 Letters Of Credit Two [Member]	Dec. 31, 2011 Letters Of Credit Three [Member]	Nov. 30, 2011 Letters Of Credit Three [Member]	Dec. 31, 2011 Guarantee Credit Line [Member]	Nov. 30, 2011 Guarantee Credit Line [Member]	Nov. 30, 2010 Guarantee Credit Line [Member]	Dec. 31, 2011 Cash Borrowing And Letter Of Credit [Member]	Nov. 30, 2011 Additional Borrowings For Letters Of Credit Or Cash [Member]	Nov. 30, 2011 Maximum [Member]	Dec. 19, 2011 Maximum [Member]	Nov. 30, 2011 Maximum [Member] Swing Line Loans [Member]	Nov. 30, 2011 Minimum [Member]	Dec. 19, 2011 Minimum [Member]	Nov. 30, 2011 Minimum [Member] Swing Line Loans [Member]	Nov. 30, 2011 Repayment of Debt July 1, 2013 [Member] Mortgage Note [Member]	Nov. 30, 2011 United States [Member] Financial Institution [Member]
Line of Credit Facility [Line Items]
Mortgage note payable, face amount		$ 54,000,000
Mortgage note payable amortization period (years)		20
Mortgage note payable fixed interest rate						5.50%
Debt principal					40,400,000																																34,400,000
Debt maturity date							Jul. 01, 2013															Jul. 01, 2012
Term on principal balance (in years)							10
Minimum cash reserve for acquiring another company without consent of lender																																		50,000,000
Revolving credit facility, maximum capacity								150,000,000		250,000,000	150,000,000			25,000,000	50,000,000	10,000,000	10,000,000	250,000,000	20,000,000										20,000,000	5,600,000
Guarantee facility, maximum capacity																										13,400,000	13,400,000
Revolving credit facility, increase in cash borrowings									100,000,000	100,000,000
Revolving credit facility amount outstanding										100,000,000			30,000,000							13,000,000	13,000,000	1,000,000	1,000,000	400,000	400,000
Irrevocable letters of credit			3
Margin on base rates																																1.00%	3.00%		0.25%	2.25%
Basis spread on variable rate																															3.00%			2.25%
Spread over LIBOR	1.00%																														4.00%	2.00%		3.25%	1.25%
Base rate spread over LIBOR			1.00%
LIBOR interest period (in months)	1		1
Base rate spread over federal fund rate			0.50%
Line of credit facility, commitment fee percentage																															0.75%			0.50%
Loan origination fee and issuance costs	2,000,000			2,317,000
Interest expense amortization period (in years)			3
Renewal period (in years)														1
Default applicable interest rate on all obligations			2.00%
Consolidated cash balance to be maintained after acquisition			120,000,000																																			80,000,000
Interest coverage ratio																																		3.5	3.5
Leverage ratio																															2.5	2.5
Revolving credit facility, maturity date												December 19, 2016
Bank guarantees																											11,400,000	8,600,000
Restricted cash			$ 13,800,000		$ 10,500,000