Convertible Debentures and Revolving Credit Facility (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Jun. 30, 2012	Jul. 02, 2011
Debt Instrument [Line Items]
Amortization of debt discount	$ 3,938	$ 3,856
2.625% Senior Convertible Debentures [Member]
Debt Instrument [Line Items]
Contractual coupon interest	3,938	3,938
Amortization of debt issuance costs	362	362
Amortization of debt discount	2,763	2,763
Total interest expense related to the debentures	7,063	7,063
3.125% Junior Convertible Debentures [Member]
Debt Instrument [Line Items]
Contractual coupon interest	5,388	5,388
Amortization of debt issuance costs	56	56
Amortization of embedded derivative	15	15
Amortization of debt discount	1,175	1,093
Fair value adjustment of embedded derivative	614	(373)
Total interest expense related to the debentures	$ 7,248	$ 6,179