Marketable Securities (Narratives) (Details) (USD $)	3 Months Ended		9 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 month	Dec. 31, 2011
Marketable Securities [Abstract]
Marketable Securities, Realized Loss, Other than Temporary Impairments, Description			The Company generally considers market value declines to be other-than-temporary if there are declines for a period longer than six months and in excess of 20% of original cost, or when other evidence indicates impairment.
Minimum Decline In Value Of Marketable Securities To Be Called As Other Than Temporaty Impairment Period			6
Minimum Decline In Value Of Marketable Securities To Be Called As Other Than Temporary Impairment Percent			20.00%
Marketable Securities, Realized Gain (Loss)	$ 147,000	$ 31,000	$ 399,000	$ 152,000