Note 3 - Receivables (Detail) - Credit Risk Profile by Internally Assigned Grade (USD $) In Millions, unless otherwise specified	Mar. 31, 2013		Sep. 30, 2012
Recorded Investment by Credit Quality Indicator	$ 412.4		$ 430.3
Low [Member] | Contracts [Member]
Recorded Investment by Credit Quality Indicator	80.1		87.8
Low [Member]
Recorded Investment by Credit Quality Indicator	80.1		87.8
Medium [Member] | Contracts [Member]
Recorded Investment by Credit Quality Indicator	66.2		68.3
Medium [Member] | Notes [Member]
Recorded Investment by Credit Quality Indicator	0.1		0.2
Medium [Member]
Recorded Investment by Credit Quality Indicator	66.3		68.5
High [Member] | Contracts [Member]
Recorded Investment by Credit Quality Indicator	159.1		152.3
High [Member] | Notes [Member]
Recorded Investment by Credit Quality Indicator	106.9		121.7
High [Member]
Recorded Investment by Credit Quality Indicator	266.0	[1]	274.0	[1]
Contracts [Member]
Recorded Investment by Credit Quality Indicator	305.4		308.4
Notes [Member]
Recorded Investment by Credit Quality Indicator	$ 107.0		$ 121.9

[1] includes $75.0 of impaired Alabama notes receivable