Stock-Based Compensation Plans (Tables) - Summary of Stock Activity (Details) (USD $) In Thousands, except Share data, unless otherwise specified	6 Months Ended
	Mar. 31, 2014 Years	Sep. 30, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Options outstanding at October 1, 2013	414,590
Options granted	31,790
Options exercised	55,699
Options outstanding at March 31, 2014	390,681
Options outstanding weighted average exercise price-beginning balance	$ 20.40
Options outstanding weighted average exercise price - Granted	$ 41.39
Options outstanding weighted average exercise price - Exercised	$ 12.01
Options outstanding weighted average exercise price - Ending balance	$ 23.30
Options outstanding weighted average remaining term	4.7	4.2
Options outstanding weighted average grant date fair value - beginning balance	$ 3,668
Options granted weighted average grant date fair value	545
Options exercised weighted average grant date fair value	335
Options outstanding weighted average grant date fair value - ending balance	3,878
Options exercisable at March 31, 2014	303,527
Options exerciseable weighted average exercise price	$ 21.39
Options exerciseable weighted average remaining term	3.6
Options exerciseable weighted average grant date fair value	2,745
Options vested during six months ended March 31, 2014	28,348
Options vested weighted average grant date fair value	$ 322