Derivative Instruments and Hedging Activities (Details 4) (USD $)	6 Months Ended
	Mar. 31, 2013 item
Forward starting swap
Derivative instruments and hedging activities
Debt to be issued under derivative contacts	$ 83,000,000
Term of debt to be issued	10 years
Term of derivative contract	10 years
Number of semi-annual interest cash flows	20
Notional Principal outstanding derivative instruments	58,400,000
Fixed rate (as a percent)	1.698%
Variable rate basis	3-month LIBOR
Number of days prior to the first day of each calculation period	2 days
Foreign currency forwards
Derivative instruments and hedging activities
Minimum commitment amount for hedging	$ 50,000