Pensions and Other Post-retirement Benefits (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 Benefit Cost
Interest cost	$ 1,115	$ 1,171	$ 2,231	$ 2,342
Expected return on plan assets	(1,490)	(1,743)	(2,980)	(3,486)
Recognized net actuarial loss	493	309	986	618
Settlement	1,454		1,454
Net pension expense (benefit)	$ 1,572	$ (263)	$ 1,691	$ (526)