Pension Plans (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2016	Mar. 31, 2015
Components of net periodic pension cost (benefit)
Service cost	$ 152	$ 167	$ 310	$ 339
Interest cost	2,279	2,253	4,540	4,585
Expected return on plan assets	(3,303)	(3,492)	(6,775)	(6,880)
Amortization of actuarial loss	499	184	912	338
Administrative expenses	45	41	86	79
Net pension benefit	$ (328)	$ (847)	$ (927)	$ (1,539)