Stock Based Compensation (Restricted Stock) (Details) (USD $) In Millions, except Share data, unless otherwise specified		12 Months Ended			1 Months Ended		3 Months Ended		12 Months Ended	3 Months Ended		12 Months Ended
	Sep. 30, 2012 2006 Plan [Member]	Sep. 30, 2012 Restricted Stock [Member]	Sep. 30, 2011 Restricted Stock [Member]	Sep. 30, 2010 Restricted Stock [Member]	Aug. 31, 2012 Restricted Stock [Member] 2006 Plan [Member]	Jun. 30, 2012 Restricted Stock [Member] 2006 Plan [Member]	Dec. 31, 2010 Restricted Stock [Member] 2006 Plan [Member]	Dec. 31, 2009 Restricted Stock [Member] 2006 Plan [Member]	Sep. 30, 2012 Restricted Stock [Member] 2006 Plan [Member]	Dec. 31, 2010 Restricted Stock [Member] Maximum [Member] 2006 Plan [Member]	Dec. 31, 2010 Restricted Stock [Member] Minimum [Member] 2006 Plan [Member]	Sep. 30, 2012 Stock Options [Member]	Sep. 30, 2012 Stock Options [Member] Non Employee Director Stock Option Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock issuable to eligible Board of Directors members annually		2,000
Maximum aggregate number of shares to be issued under the plan		150,000
Number of shares authorized	750,000
Number of shares available for grant	508,403	32,879											33,117
Shares issued under the plan		16,000	17,500		45,000	2,000	26,000	10,000
Shares issued, price per share		$ 37.50	$ 33.49		$ 39.11	$ 37.50		$ 37.67		$ 32.12	$ 30.79
Vesting period		2 years			3 years	2 years	3 years	5 years				5 years
Vesting percentage per year		50.00%			33.00%	50.00%		20.00%				20.00%
Weighted average grant date fair value									$ 37.67
Shares vested							7,601	8,000
Compensation expense		$ 0.7	$ 0.8	$ 0.8