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, 2019	Sep. 30, 2018	Sep. 30, 2017
Accounting Policies [Abstract]
Net income (loss)	$ (27,460)	$ 51,987	$ 6,239
Weighted average shares outstanding (in shares)	117,724	116,390	115,523
Dilutive effect of employee stock options, restricted shares and restricted stock units (in shares)	0	1,768	1,833
Diluted weighted average shares outstanding (in shares)	117,724	118,158	117,356
Basic earnings (loss) per share (in USD per share)	$ (0.23)	$ 0.45	$ 0.05
Diluted earnings (loss) per share (in USD per share)	$ (0.23)	$ 0.44	$ 0.05