Stock-based Compensation Plans - Summary of Stock Activity (Details) (USD $) In Thousands, except Share data, unless otherwise specified	9 Months Ended
	Jun. 30, 2012 Y	Sep. 30, 2011
Notes to Financial Statements
Options outstanding at October 1, 2011	606,025
Options granted	31,690
Options exercised	96,041
Options forfeited	3,000
Options outstanding at June 30, 2012	538,674
Options outstanding weighted average exercise price-beginning balance	$ 14.96
Options outstanding weighted average exercise price - Granted	$ 22.25
Options outstanding weighted average exercise price - Exercised	$ 8.68
Options outstanding weighted average exercise price - Forfeited	$ 5.78
Options outstanding weighted average exercise price - Ending balance	$ 16.56
Options outstanding weighted average remaining term	3.7	3.5
Options outstanding weighted average grant date fair value - beginning balance	$ 4,216
Options granted weighted average grant date fair value	281
Options exercised weighted average grant date fair value	452
Options forfeited weighted average grant date fair value	10
Options outstanding weighted average grant date fair value - ending balance	4,035
Options exercisable at June 30, 2012	463,430
Options exerciseable weighted average exercise price	$ 15.13
Options exerciseable weighted average remaining term	2.9
Options exerciseable weighted average grant date fair value	3,238
Options vested during nine months ended June 30, 2012	30,774
Options vested weighted average grant date fair value	$ 319