Employee Benefit Plans (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost for benefits earned during the period	$ 155	$ 129
Interest cost on accumulated postretirement benefit	139	142
Other components	1	(4)
Net periodic postretirement benefit cost	$ 295	$ 267