Certain Financial Statement Information Gross Unrealized Losses (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
	Dec. 31, 2014	Mar. 31, 2014
Schedule of Gross Unrealized Losses
Less Than 12 Months of Unrealized Losses, Estimated Fair Value	$ 4,086	$ 6,242
Less than 12 Months of Unrealized Losses, Gross Unrealized Losses	(13)	(351)
12 Months or More of Unrealized Losses, Estimated Fair Value	4,376	405
12 Months or More of Unrealized Losses, Gross Unrealized Losses	(204)	(69)
Total, Estimated Fair Value	8,462	6,647
Total Gross Unrealized Losses	(217)	(420)
Corporate bonds [Member]
Schedule of Gross Unrealized Losses
Less Than 12 Months of Unrealized Losses, Estimated Fair Value	3,750	992
Less than 12 Months of Unrealized Losses, Gross Unrealized Losses	(9)	(2)
12 Months or More of Unrealized Losses, Estimated Fair Value	0	0
12 Months or More of Unrealized Losses, Gross Unrealized Losses	0	0
Total, Estimated Fair Value	3,750	992
Total Gross Unrealized Losses	(9)	(2)
Mortgage-backed and asset-backed securities [Member]
Schedule of Gross Unrealized Losses
Less Than 12 Months of Unrealized Losses, Estimated Fair Value	275	431
Less than 12 Months of Unrealized Losses, Gross Unrealized Losses	(2)	(16)
12 Months or More of Unrealized Losses, Estimated Fair Value	121	0
12 Months or More of Unrealized Losses, Gross Unrealized Losses		0
Total, Estimated Fair Value	396	431
Total Gross Unrealized Losses	(2)	(16)
Closed-end bond funds [Member]
Schedule of Gross Unrealized Losses
Less Than 12 Months of Unrealized Losses, Estimated Fair Value	61	4,819
Less than 12 Months of Unrealized Losses, Gross Unrealized Losses	(2)	(333)
12 Months or More of Unrealized Losses, Estimated Fair Value	4,255	405
12 Months or More of Unrealized Losses, Gross Unrealized Losses	(204)	(69)
Total, Estimated Fair Value	4,316	5,224
Total Gross Unrealized Losses	$ (206)	$ (402)