Interest Rate Swaps (Narrative) (Details) (USD $)	1 Months Ended	3 Months Ended		9 Months Ended
	Feb. 29, 2012 Swap	Jun. 30, 2012 Swap	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Sep. 30, 2011
Summary of Derivative Instruments by Risk Exposure [Line Items]
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax, Portion Attributable to Parent		$ (556,000)	$ 0	$ (1,116,000)	$ 0
Number of interest rate swap agreements		5		5
Notional amount of interest rate swap agreements		150,000,000		150,000,000		250,000,000
Number of suspended derivative swaps	4
Number of suspended swaps that became active		2
Outstanding credit facility		150,000,000		150,000,000
Interest rate fixed as result of interest rate swap hedges				3.50%
Unrealized loss recognized in OCI		600,000		1,100,000
Unrealized loss recognized on statement of operations		0		400,000
Interest Rate Swap [Member]
Summary of Derivative Instruments by Risk Exposure [Line Items]
Number of interest rate swap agreements		2		2
3.4% Interest Rate Swaps Due 2014 [Member]
Summary of Derivative Instruments by Risk Exposure [Line Items]
Number of interest rate swap agreements		5		5
Number of Interest Rate Derivatives Held In Effect to Fix Interest Rate		3		3
Outstanding credit facility		$ 250,000,000		$ 250,000,000
Interest rate fixed as result of interest rate swap hedges				3.40%
Maximum [Member]
Summary of Derivative Instruments by Risk Exposure [Line Items]
Derivative swap suspension period, in months	5
Minimum [Member]
Summary of Derivative Instruments by Risk Exposure [Line Items]
Derivative swap suspension period, in months	2