Notes Payable and Long-Term Debt (Details) In Thousands, unless otherwise specified	1 Months Ended		12 Months Ended			12 Months Ended	3 Months Ended		12 Months Ended		12 Months Ended
	Jun. 30, 2013 Credit Agreement USD ($)	Aug. 31, 2012 Credit Agreement USD ($)	Dec. 31, 2013 Credit Agreement USD ($)	Mar. 31, 2013 Credit Agreement USD ($)	Dec. 31, 2012 Credit Agreement USD ($)	Dec. 31, 2013 Credit Agreement Minimum USD ($)	Sep. 30, 2013 Credit Agreement Maximum	Jun. 30, 2013 Credit Agreement Maximum	Dec. 31, 2013 Credit Agreement Maximum USD ($)	Dec. 31, 2013 Credit Agreement LIBOR based interest rates	Dec. 31, 2013 Credit Agreement LIBOR based interest rates First 30 days	Dec. 31, 2013 Credit Agreement LIBOR based interest rates Thereafter	Dec. 31, 2013 Credit Agreement LIBOR based interest rates Thereafter Minimum	Dec. 31, 2013 Credit Agreement LIBOR based interest rates Thereafter Maximum	Dec. 31, 2013 Credit Agreement Alternate Base Rate based interest rates First 30 days	Dec. 31, 2013 Credit Agreement Alternate Base Rate based interest rates Thereafter	Dec. 31, 2013 China Credit Agreement USD ($)	Dec. 31, 2013 China Credit Agreement CNY
Notes Payable and Long-Term Debt
Term of agreement (in years)		5 years
Current borrowing capacity		$ 400,000																60,000
Maximum available for the issuance of letters of credit		75,000
Maximum available for swing loans		5,000
Additional available credit		100,000
Spread on variable interest rate (as a percent)			1.25%								1.75%		1.50%	2.25%	0.75%	0.50%
Variable interest rate basis												LIBOR
Period of variable interest rate basis (in days)			30 days
Adjusted LIBOR rate at period end (as a percent)										0.17%
Fees on the daily unused amount (as a percent)			0.25%			0.20%			0.35%
Outstanding borrowings																	10,000
Outstanding letters of credit			200
Unused balance under credit agreement			399,800
Amount available under the Credit Agreement			251,800
Additional Financial Covenants Required
Asset coverage ratio, numerator, to be maintained under Credit Agreement covenants						1.10
Ratio of consolidated EBITDA plus annual rental expense to annual interest expense plus annual rental expense, numerator, to be maintained under Credit Agreement covenants						2.25
Additional secured debt related to a capital asset allowed under Credit Agreement covenants									65,000
Unsecured debt allowed under Credit Agreement covenants for new corporate headquarters									75,000
Additional unsecured debt allowed under Credit Agreement covenants									200,000
Secured debt not related to a capital asset allowed under Credit Agreement covenants									5,000
Amount of judgment allowed under Credit Agreement covenants									10,000
Amount of ERISA event in one year allowed under Credit Agreement covenants									10,000
Amount of ERISA event in all years allowed under Credit Agreement covenants									20,000
Maximum limit on acquisitions under terms of the Credit Agreement covenants									100,000
Total adjusted leverage ratio, numerator, to allow for maximum limit on acquisitions under terms of the Credit Agreement covenants							3.25	2.75	2.75
Amount of cash plus unused credit to allow for no limit on acquisitions						75,000
Amount of cash plus unused credit to allow for no limit on share repurchases for first , second and fourth quarter						150,000
Amount of cash plus unused credit to allow for no limit on share repurchases for third quarter						75,000
Debt Instrument Covenant Borrowings Allowed in Third and Fourth Quarters of Fiscal Year																	10,000	60,000
Debt Instrument Covenant Borrowings Allowed in First and Second Quarters of Fiscal Year																	3,300	20,000
Debt Instrument, Interest Rate, Effective Percentage																	6.00%	6.00%
Debt Instrument Covenant Percentage of Facility Amount in United States Dollars Guaranteed																	110.00%	110.00%
Increase in additional borrowings allowed per amendment	12,500
Additional borrowings related to headquarters allowed under Credit Agreement covenants prior to amendment	80,000			75,000
Deferred financing costs					$ 1,800