Fair Value Measurements (Details) (Recurring Basis [Member], USD $) In Thousands, unless otherwise specified	Apr. 26, 2014		Apr. 27, 2013
Level 1 [Member]
Assets [Abstract]
Available-for-sale securities	$ 1,521	[1]	$ 1,217	[2]
Trading securities	0	[1]	0	[2]
Total	1,521	[1]	1,217	[2]
Level 2 [Member]
Assets [Abstract]
Available-for-sale securities	57,630	[1]	38,747	[2]
Trading securities	1,787	[1]	1,126	[2]
Total	59,417	[1]	39,873	[2]
Level 3 [Member]
Assets [Abstract]
Available-for-sale securities	0		0
Trading securities	0		0
Total	$ 0		$ 0

[1] There were no transfers between Level 1 and Level 2 during fiscal 2014.

[2] There were no transfers between Level 1 and Level 2 during fiscal 2013.