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 Loss
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	46,218			46,218
Other comprehensive income	1,025				1,025
Restricted stock awards (in shares)		137
Vesting of restricted stock awards	0	(137)	(137)
Exercise of employee stock options (in shares)		52
Exercise of employee stock options	784	52	732
Stock option and restricted stock award compensation expense	4,024		4,024
Ending Balance at Dec. 31, 2014	$ 2,607,575	$ 64,551	$ 206,083	$ 2,332,355	$ 4,586
Ending Balance (in shares) at Dec. 31, 2014		64,551