Summary Of Significant Accounting Policies (Earnings Per Share Basic And Diluted) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Accounting Policies [Abstract]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount			1,700
Net income (loss)	$ 51,987	$ 6,239	$ (54,465)
Weighted average shares outstanding (in shares)	116,390	115,523	114,612
Dilutive effect of employee stock options, restricted shares and restricted stock units (in shares)	1,768	1,833	0
Diluted weighted average shares outstanding (in shares)	118,158	117,356	114,612
Basic earnings (loss) per share (in USD per share)	$ 0.45	$ 0.05	$ (0.48)
Diluted earnings (loss) per share (in USD per share)	$ 0.44	$ 0.05	$ (0.48)