Employee Benefit Plans (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Postretirement Benefits [Member]
Components of the net periodic benefit cost
Interest cost	$ 8	$ 9
Amortization of net loss	2	4
Net periodic cost	10	13
Pension Plan [Member]
Components of the net periodic benefit cost
Interest cost	35	43
Net periodic cost	$ 35	$ 43