Earnings Per Common Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013	Mar. 31, 2012
Earnings Per Common Share Details [Abstract]
Net income	$ 15,100	$ 13,178	$ 31,851	$ 26,374
Weighted Average Number of Shares Outstanding, Basic	12,674	12,619	12,669	12,600
Effect Of Dilutive Securities [Abstract]
Stock Options And Restricted Stock Diluted Shares	35	29	33	26
Weighted Average Number of Shares Outstanding, Diluted	12,709	12,648	12,702	12,626
Basic EPS	$ 1.19	$ 1.04	$ 2.51	$ 2.09
Diluted EPS	$ 1.19	$ 1.04	$ 2.51	$ 2.09
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0	0	0	0