Credit Facilities (Narrative) (Details) (USD $)	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Debt Instrument [Line Items]
Number Of Years Of Bank Credit Agreement	5
Amount under revolving credit facility	$ 450,000,000
Fully funded amortizing term loan	100,000,000
Amount Outstanding under revolving credit facility	0
Outstanding uncommitted lines of credit	105,318,000	128,016,000
Weighted average interest rates on short-term borrowings outstanding	3.80%	7.10%
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maturity date of credit facility	Nov. 01, 2016
Prime Rate Or One Month LIBOR [Member]
Debt Instrument [Line Items]
Margin rate on credit	1.00%
Federal Funds Rate [Member]
Debt Instrument [Line Items]
Margin rate on credit	0.50%
Uncommitted lines of credit [Member]
Debt Instrument [Line Items]
Outstanding uncommitted lines of credit	105,000,000	128,000,000
Unused Lines Of Credit [Member]
Debt Instrument [Line Items]
Outstanding uncommitted lines of credit	$ 307,000,000