Accounting for Share-Based Compensation 3 (Details) - $ / shares		6 Months Ended
		Sep. 30, 2016	Sep. 30, 2015
Weighted average fair values and assumptions used for options granted
Weighted average fair value (in dollars per share)		$ 4.41	$ 4.68
Dividend yield		3.57%	3.37%
Expected volatility factor	[1]	22.00%	23.00%
Risk-free interest rate	[2]	1.50%	1.90%
Expected life (in years)	[3]	6 years	6 years

[1] Expected volatility is measured using historical daily price changes of the Company’s common stock over the respective expected term of the options and the implied volatility derived from the market prices of the Company’s traded options.

[2] The risk-free rate for periods within the contractual term of the stock options is based on the U.S. Treasury yield curve in effect at the time of grant.

[3] The expected life is the number of years the Company estimates that options will be outstanding prior to exercise. The Company’s computation of expected life was determined based on the simplified method (the average of the vesting period and option term).