Pension Plans (Details) (Defined Benefit Pension Plans, USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013	Mar. 31, 2012
Defined Benefit Pension Plans
Components of net periodic pension cost (benefit)
Service cost	$ 136	$ 127	$ 276	$ 254
Interest cost	2,217	2,391	4,461	4,782
Expected return on plan assets	(2,900)	(2,523)	(5,834)	(5,046)
Amortization of actuarial loss	450	398	907	796
Administrative expenses	19	21	38	42
Net pension cost (benefit)	$ (78)	$ 414	$ (152)	$ 828