Unaudited Condensed Consolidated Statement Of Changes In Shareholders' Equity (USD $) In Thousands, unless otherwise specified	Total	Common Stock	Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income
Beginning Balance at Sep. 30, 2014	$ 2,555,524	$ 64,362	$ 201,464	$ 2,286,137	$ 3,561
Beginning Balance (in shares) at Sep. 30, 2014		64,362
Increase (Decrease) in Stockholders' Equity
Net income	168,887			168,887
Other comprehensive income	2,690				2,690
Dividends declared	(16,234)			(16,234)
Restricted stock awards (in shares)		222
Vesting of restricted stock awards	(1,955)	(222)	(2,177)
Exercise of employee stock options (in shares)		60
Exercise of employee stock options	918	60	858
Stock option and restricted stock award compensation expense	8,119		8,119
Ending Balance at Mar. 31, 2015	$ 2,717,949	$ 64,644	$ 208,264	$ 2,438,790	$ 6,251
Ending Balance (in shares) at Mar. 31, 2015		64,644