Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 20,578	$ 20,718
Other comprehensive income (loss), net of tax:
Changes in unrealized holding gains (losses) on AFS securities, net of taxes of $799 and $1,700	(1,314)	(2,798)
Comprehensive income	$ 19,264	$ 17,920