CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
Tax on unrealized gain (loss) on available for sale securities	$ 1,499	$ (1,135)	$ 426
Tax on net unrealized gain (loss) on derivatives	0	(56)	61
Tax on adjustment to postemployment benefit obligation	$ 2,466	$ 3,688	$ 2,162