Earnings Per Common Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Calculation of earnings per share basic and diluted [Abstract]
Net earnings available to common stockholders	$ 10,736	$ 9,207	$ 30,851	$ 26,122
Weighted average number of common share equivalents:
Common shares used in basic earnings per share	6,374,083	6,257,336	6,363,126	6,180,576
Common share equivalents outstanding related to stock options	67,141	117,820	63,059	113,228
Total weighted average common shares and common share equivalents used in diluted earnings per share	6,441,224	6,375,156	6,426,185	6,293,804
Basic earnings per common share	$ 1.68	$ 1.47	$ 4.85	$ 4.23
Diluted earnings per common share	$ 1.67	$ 1.44	$ 4.80	$ 4.15