CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement of Comprehensive Income [Abstract]
Tax on unrealized (loss) gain on available for sale securities	$ 2,375	$ 3,754	$ (2,081)	$ (2,014)
Tax on net unrealized (loss) gain on derivatives	0	2	0	0
Tax on adjustment for postemployment benefit obligation	$ (217)	$ (174)	$ (651)	$ (523)