General (Details1) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Feb. 28, 2013	Feb. 23, 2012	Feb. 28, 2013	Feb. 23, 2012
Numerator:
Net earnings (loss)	$ (1,372)	$ 734	$ 14,031	$ 16,035
Denominator:
Denominator for basic EPS	27,254	29,172	28,105	29,331
Effect of dilutive employee stock options	20	37	19	31
Denominator for diluted EPS	27,274	29,209	28,124	29,362
Common Stock [Member]
Net earnings (loss) per share - basic:
Common Stock	$ (0.05)	$ 0.03	$ 0.56	$ 0.56
Net earnings (loss) per share - diluted:
Common Stock	$ (0.05)	$ 0.03	$ 0.50	$ 0.55
Class B Common Stock [Member]
Net earnings (loss) per share - basic:
Common Stock	$ (0.05)	$ 0.02	$ 0.48	$ 0.51
Net earnings (loss) per share - diluted:
Common Stock	$ (0.05)	$ 0.02	$ 0.48	$ 0.51