Note 8 - Equity Plans (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended				0 Months Ended		3 Months Ended	12 Months Ended			3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Jan. 02, 2013	Jan. 03, 2012	Jan. 02, 2013 Restricted Stock Units (RSUs) [Member]	Jan. 03, 2012 Restricted Stock Units (RSUs) [Member]	Mar. 31, 2013 Restricted Stock Units (RSUs) [Member]	Dec. 31, 2011 Purchase Requirement [Member]	Dec. 31, 2011 Matching Purchase Requirement [Member]	Dec. 31, 2011 Match [Member]	Mar. 31, 2013 Five Year Anniversary [Member]	Mar. 31, 2013 Ten Year Anniversary [Member]	Mar. 31, 2013 Fifteen Year Anniversary [Member]	Mar. 31, 2013 Twenty Year Anniversary [Member]	Mar. 31, 2013 Twenty Five Year Anniversary [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	1,667	2,170
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value (in Dollars)	$ 28	$ 52
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	500,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period					1,800	1,800	37,341
Share Price (in Dollars per share)			$ 23.41	$ 25.55
Share-based Compensation Arrangement by Share-based Payment Award, Description								750	500	250
Shares Matched	6,000	3,250
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Intrinsic Value (in Dollars per share)							$ 135				$ 25,000	$ 50,000	$ 75,000	$ 100,000	$ 100,000