Consolidated Statements Of Comprehensive Income (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Statement of Comprehensive Income [Abstract]
Net income	$ 77,694	$ 69,340	$ 74,513
Other comprehensive income (loss), net of tax:
Changes in unrealized holding losses on AFS securities, net of deferred income taxes of $171, $10,295, and $1,491 for the years ended September 30, 2014, 2013 and 2012, respectively	(281)	(16,940)	(2,500)
Comprehensive income	$ 77,413	$ 52,400	$ 72,013