Postretirement Life and Medical Insurance Benefits to Eligible Retirees (Details) (USD $)	12 Months Ended
	Mar. 31, 2013 age
Health insurance
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Deferred compensation arrangement with individuals, description	Retirees must have attained age sixty-five and earned twenty years of full-time service upon retirment for coverage under the medical plan. The medical benefits are capped at a $20,000 lifetime maximum per covered person. The benefits are coordinated with Medicare and any other medical policies in force.
Age requirement for retiring	65
Deferred compensation arrangement with individual, requisite service period	Twenty years
Lifetime maximum benefit paid per individual	$ 20,000
Life insurance
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Deferred compensation arrangement with individuals, description	Retirees who have attained the age sixty-five and earned at least ten years of full-time service upon retirement from the Company are entitled to group term life insurance benefits. The life insruance benefit is $2,000 plus $100 for each year of employment over ten years. The plan is not funed and claims are paid as they are incurred
Age requirement for retiring	65
Deferred compensation arrangement with individual, requisite service period	Ten years
Lifetime maximum benefit paid per individual	2,000
Additional benefit stipulation for life insurance	10 years 0 months 0 days
Additional benefit requirement amount	$ 100