Investments (Details 2) (USD $) In Thousands, unless otherwise specified	Dec. 29, 2012	Mar. 31, 2012
Contractual Maturity of Investment Securities
Due in less than one year, Amortized Cost	$ 2,076	$ 1,355
Due after one year through five years, Amortized Cost	4,807	5,498
Due after five years through ten years, Amortized Cost	744	260
Due after ten years, Amortized Cost	4,777	3,030
Total Amortized Cost	12,404	10,143
Due in less than one year, Fair Value	2,088	1,359
Due after one year through five years, Fair Value	4,907	5,573
Due after five years through ten years, Fair Value	715	270
Due after ten years, Fair Value	4,702	2,982
Total Fair Value	$ 12,412	$ 10,184