Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Net earnings	$ 61,750	$ 67,756	$ 58,492	$ 57,995	$ 64,812	$ 72,466	$ 64,889	$ 58,983	$ 245,993	$ 261,151	$ 233,064
Total weighted average basic shares									159,933,000	171,682,000	183,420,000
Dilutive securities:
Stock options and stock award programs (in shares)									3,486,000	4,477,000	5,190,000
Total weighted average diluted shares									163,419,000	176,159,000	188,610,000
Earnings per share:
Basic (in dollars per share)	$ 0.40	$ 0.43	$ 0.36	$ 0.35	$ 0.39	$ 0.43	$ 0.37	$ 0.33	$ 1.54	$ 1.52	$ 1.27
Diluted (in dollars per share)	$ 0.39	$ 0.42	$ 0.35	$ 0.35	$ 0.38	$ 0.42	$ 0.36	$ 0.32	$ 1.51	$ 1.48	$ 1.24
Common stock potentially outstanding but not included in the computation of diluted earnings per share
Options to purchase shares not included in the computation of diluted earnings per share since the options were anti-dilutive (in shares)									130,952		44,340