Pension and Other Post-retirement Benefit Plans (Details 3) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Pension
Projected benefit obligation:
Discount rate	4.50%	4.50%
Rate of compensation increase	3.40%	3.50%
Net periodic benefit cost:
Discount rate	4.50%	4.20%
Rate of compensation increase	3.50%	2.90%
Expected return on plan assets	4.90%	4.00%
Other Benefits
Projected benefit obligation:
Discount rate	3.40%	2.80%
Rate of compensation increase	0.00%	0.00%
Health care cost trend on covered charges	7.00%	7.00%
Ultimate health care cost trend on covered charges	5.00%	5.00%
Net periodic benefit cost:
Discount rate	2.80%	3.50%
Rate of compensation increase	0.00%	0.00%
Expected return on plan assets	0.00%	0.00%
Health care cost trend on covered charges	7.00%	7.50%
Ultimate health care cost trend on covered charges	5.00%	5.00%
Effect of a one percentage point increase in assumed health care cost trend:
—On total service and interest costs components	$ 0	$ 0
—On post-retirement benefits obligation	15	11
Effect of a one percentage point decrease in assumed health care cost trend:
—On total service and interest costs components	0	0
—On post-retirement benefits obligation	$ (13)	$ (10)