Supplemental Financial Information Comprehensive Income (Schedule of Changes in the Components of AOCI) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at March 31, 2013	$ 6,935	$ 3,101
Other comprehensive income (loss) before reclassifications	(4,289)	4,177
Amounts reclassified from accumulated other comprehensive income (loss)	(1,595)	(343)
Net other comprehensive income (loss)	(5,884)	3,834
Balance at March 31, 2014	1,051	6,935
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at March 31, 2013	5,444	3,101
Other comprehensive income (loss) before reclassifications	(4,377)	2,686
Amounts reclassified from accumulated other comprehensive income (loss)	(1,595)	(343)
Net other comprehensive income (loss)	(5,972)	2,343
Balance at March 31, 2014	(528)	5,444
Accumulated Defined Benefit Plans Adjustment [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at March 31, 2013	52	0
Other comprehensive income (loss) before reclassifications	88	52
Amounts reclassified from accumulated other comprehensive income (loss)	0	0
Net other comprehensive income (loss)	88	52
Balance at March 31, 2014	140	52
Accumulated Translation Adjustment [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at March 31, 2013	1,439	0
Other comprehensive income (loss) before reclassifications	0	1,439
Amounts reclassified from accumulated other comprehensive income (loss)	0	0
Net other comprehensive income (loss)	0	1,439
Balance at March 31, 2014	$ 1,439	$ 1,439