Pension and Post-retirement Benefits (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Defined Benefit Pension Plans
Pension Plan and Retirement Benefits
Service cost	$ 1,020	$ 975	$ 3,060	$ 2,924
Interest cost	2,549	2,787	8,262	8,010
Expected return	(2,978)	(3,761)	(9,753)	(10,807)
Amortizations	2,320	1,381	7,086	4,097
Net periodic benefit cost	2,911	1,382	8,655	4,224
U.S. pension plan
Pension Plan and Retirement Benefits
Employer contribution			4,500
Expected future employer contribution			1,500
U.K. pension plan
Pension Plan and Retirement Benefits
Employer contribution			651
Expected future employer contribution			200
Postretirement Health Care Benefits
Pension Plan and Retirement Benefits
Service cost	58	84	174	253
Interest cost	1,149	1,097	3,447	3,289
Amortizations	706	608	2,118	1,825
Net periodic benefit cost	$ 1,913	$ 1,789	5,739	$ 5,367
Employer contribution			4,569
Expected future employer contribution			$ 1,250