Earnings Per Share (Reconciliation of Net Earnings to Net Earnings Per Share Basic and Diluted) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Earnings Per Share
Net earnings	$ 28,302	$ 36,056	$ 95,470	$ 90,545
Basic shares outstanding	68,922	68,793	68,973	68,785
Dilutive effect of stock options	1,397	1,373	1,473	1,370
Diluted shares outstanding	70,319	70,166	70,446	70,155
Basic earnings per share	$ 0.41	$ 0.52	$ 1.38	$ 1.32
Diluted earnings per share	$ 0.40	$ 0.51	$ 1.36	$ 1.29