Net Periodic Benefit Cost (Components of net periodic pension cost and net periodic postretirement benefit cost) (Details) - USD ($)	3 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Curtailments	$ 247,000
Pension Plans, Defined Benefiit
Defined Benefit Plan Disclosure [Line Items]
Service costs	451,000	$ 517,000
Interest cost	4,115,000	2,459,000
Expected return on plan assets	(5,619,000)	(3,679,000)
Net amortization	794,000	909,000
Defined Benefit Plan, Curtailments	247,000	0
Net periodic pension (benefit) cost	(12,000)	206,000
Other Postretirement Benefit Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Interest cost	42,000	51,000
Net periodic pension (benefit) cost	51,000	84,000
Amortization of plan net losses	$ 9,000	$ 33,000