Certain Financial Statement Information (Details 11) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Mar. 31, 2012
Schedule of cost and estimated fair values of available-for-sale securities with stated maturities by contractual maturity
Less than 1 year, Cost	$ 13,979	$ 16,683
Mature in 1 - 2 years, Cost	18,972	26,869
Mature in 3 - 5 years, Cost	415	2,421
Mature after 5 years, Cost	1,216	1,467
Cost, Total	34,582	47,440
Less than 1 year, Fair Value	14,152	16,722
Mature in 1 - 2 years, Fair Value	19,036	27,026
Mature in 3 - 5 years, Fair Value	459	2,496
Mature after 5 years, Fair Value	1,358	1,537
Fair Value, Total	$ 35,005	$ 47,781

Available-for-sale securities, debt maturities, after five years, amortized cost.

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Available-for-sale securities, debt maturities, after five years, fair value.

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Available-for-sale securities, debt maturities, one to two years, amortized cost.

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Amount of available-for-sale debt securities at cost, net of adjustments, which include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings (less any cumulative-effect adjustments, as defined) and fair value hedge accounting adjustments.

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Amount of available-for-sale debt securities at cost, net of adjustments, maturing in the next fiscal year following the latest fiscal year. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings (less any cumulative-effect adjustments, as defined) and fair value hedge accounting adjustments.

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Amount of debt securities categorized neither as held-to-maturity nor trading.

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