Long Term Debt (Details) (USD $)	1 Months Ended	12 Months Ended					12 Months Ended					12 Months Ended		12 Months Ended
	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011	Aug. 31, 2012 banks	Sep. 30, 2010	Sep. 30, 2013 Maximum [Member]	Sep. 30, 2013 Minimum [Member]	Nov. 15, 2013 Term Loan [Member]	Sep. 30, 2013 Term Loan [Member]	Sep. 30, 2012 Term Loan [Member]	Sep. 30, 2012 Line of Credit [Member]	Sep. 30, 2013 Line of Credit [Member]	Sep. 30, 2012 Line of Credit [Member] Maximum [Member]	Sep. 30, 2012 Line of Credit [Member] Minimum [Member]	Sep. 30, 2013 LIBOR for Eurodollar-Based Borrowings [Member] Line of Credit [Member] Maximum [Member]	Sep. 30, 2013 LIBOR for Eurodollar-Based Borrowings [Member] Line of Credit [Member] Minimum [Member]	Sep. 30, 2012 Base Rate [Member] Line of Credit [Member] Maximum [Member]	Sep. 30, 2013 Base Rate [Member] Line of Credit [Member] Minimum [Member]
Debt Instrument [Line Items]
Credit facility syndicate, number of participating banks					10
Credit facility, current maximum amount										$ 150,000,000			$ 300,000,000
Credit facility, additional borrowing limit		150,000,000
Credit facility, revolving loan, repayments of principal due in 2014										15,000,000
Credit facility, revolving loan, repayments of principal due in 2015											15,000,000
Credit facility, revolving loan, repayments of principal due in 2016											22,500,000
Credit facility, revolving loan, repayments of principal due in 2017											90,000,000
Credit facility, borrowings outstanding	370,000,000	258,100,000	370,000,000			0				142,500,000			115,600,000
Borrowings under revolving credit facility	230,000,000	0	230,000,000	250,000,000
Voting interest in foreign subsidiaries pledged against credit facility		65.00%
Credit facility, variable interest rate, length of time between updates							180 days	30 days
Credit facility, term loan, interest rate at period end									1.50%	1.5625%			1.5625%
Debt Instrument, Basis Spread on Variable Rate																1.50%	1.25%	0.50%	0.25%
Credit facility, revolving loan, basis spread on federal funds effective rate												0.005%
Credit facility, revolving loan, basis spread on adjusted LIBOR												1.00%
Credit facility, revolving loan, commitment fees percentage														0.30%	0.20%
Investment limit in foreign subsidiaries	50,000,000		50,000,000
Cash investment limit for acquisition of business	75,000,000		75,000,000
Maximum leverage ratio allowed under debt covenant	2.5		2.5
Minimum fixed charge coverage ratio allowed under debt covenant	3.50		3.50
Leverage ratio, actual	0.94		0.94
Fixed charge coverage ratio, actual	18.43		18.43
Credit facility, origination costs			1,800,000	1,000,000
Credit facility, periodic interest payment		$ 5,800,000	$ 3,700,000	$ 1,500,000
Credit facility, average interest rate during period		1.70%	1.80%	2.10%