Note 13 - Stock-Based Compensation - Compensation Shares Authorized Under Stock Option Plans By Exercise Price Range (Details)	12 Months Ended
	Jan. 03, 2021 $ / shares shares
Range 1 [Member]
Options Outstanding - Lower Limit (in dollars per share)
Options Outstanding (in shares) | shares	52,000
Weighted Average Remaining Contractual Life (Year)	5 years 8 months 4 days
Weighted Average Exercise Price (in dollars per share)	$ 12.05
Options Exercisable (in shares) | shares	52,000
Options, Weighted Average Exercise Price (in dollars per share)	$ 12.05
Range 2 [Member]
Options Outstanding - Lower Limit (in dollars per share)
Options Outstanding (in shares) | shares	14,000
Weighted Average Remaining Contractual Life (Year)	2 years 9 months 25 days
Weighted Average Exercise Price (in dollars per share)	$ 26.71
Options Exercisable (in shares) | shares	14,000
Options, Weighted Average Exercise Price (in dollars per share)	$ 26.71
Range 3 [Member]
Options Outstanding - Lower Limit (in dollars per share)
Options Outstanding (in shares) | shares	3
Weighted Average Remaining Contractual Life (Year)	2 years 4 months 2 days
Weighted Average Exercise Price (in dollars per share)	$ 32.2
Options Exercisable (in shares) | shares	3
Options, Weighted Average Exercise Price (in dollars per share)	$ 32.20
Range 4 [Member]
Options Outstanding - Lower Limit (in dollars per share)
Options Outstanding (in shares) | shares	14,000
Weighted Average Remaining Contractual Life (Year)	10 months 6 days
Weighted Average Exercise Price (in dollars per share)	$ 38.92
Options Exercisable (in shares) | shares	14,000
Options, Weighted Average Exercise Price (in dollars per share)	$ 38.92
Range 5 [Member]
Options Outstanding - Lower Limit (in dollars per share)
Options Outstanding (in shares) | shares	9,000
Weighted Average Remaining Contractual Life (Year)	2 years 9 months 3 days
Weighted Average Exercise Price (in dollars per share)	$ 42.94
Options Exercisable (in shares) | shares	9,000
Options, Weighted Average Exercise Price (in dollars per share)	$ 42.91
Range 6 [Member]
Options Outstanding - Lower Limit (in dollars per share)
Options Outstanding (in shares) | shares	3,000
Weighted Average Remaining Contractual Life (Year)	3 years 4 months 2 days
Weighted Average Exercise Price (in dollars per share)	$ 46.62
Options Exercisable (in shares) | shares	3,000
Options, Weighted Average Exercise Price (in dollars per share)	$ 46.62
Range 8 [Member]
Options Outstanding - Lower Limit (in dollars per share)
Options Outstanding (in shares) | shares	14,000
Weighted Average Remaining Contractual Life (Year)	2 years 11 months 8 days
Weighted Average Exercise Price (in dollars per share)	$ 47.46
Options Exercisable (in shares) | shares	14,000
Options, Weighted Average Exercise Price (in dollars per share)	$ 47.46
Range 9 [Member]
Options Outstanding - Lower Limit (in dollars per share)
Options Outstanding (in shares) | shares	8,000
Weighted Average Remaining Contractual Life (Year)	1 year 4 months 6 days
Weighted Average Exercise Price (in dollars per share)	$ 48.72
Options Exercisable (in shares) | shares	8,000
Options, Weighted Average Exercise Price (in dollars per share)	$ 48.72
Range 10 [Member]
Options Outstanding - Lower Limit (in dollars per share)
Options Outstanding (in shares) | shares	4,000
Weighted Average Remaining Contractual Life (Year)	3 years 4 months 17 days
Weighted Average Exercise Price (in dollars per share)	$ 53.48
Options Exercisable (in shares) | shares	4,000
Options, Weighted Average Exercise Price (in dollars per share)	$ 53.48
Range 11 [Member]
Options Outstanding - Lower Limit (in dollars per share)
Options Outstanding (in shares) | shares	121,000
Weighted Average Remaining Contractual Life (Year)	3 years 9 months
Weighted Average Exercise Price (in dollars per share)	$ 28.46
Options Exercisable (in shares) | shares	121,000
Options, Weighted Average Exercise Price (in dollars per share)	$ 28.46