Note 6 - Employee Benefit Plans - Equity-based Performance Stock Units (Details)	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017	Dec. 31, 2016
Equity-based Performance Stock Units Granted in 2019 [Member]
Performance Criteria Period (Year)	3 years
Equity-based Performance Stock Units Granted in 2019 [Member] | Minimum [Member]
Range of Award	25.00%
Equity-based Performance Stock Units Granted in 2019 [Member] | Maximum [Member]
Range of Award	200.00%
Equity-based Performance Stock Units Granted in 2018 [Member]
Performance Criteria Period (Year)		3 years
Equity-based Performance Stock Units Granted in 2018 [Member] | Minimum [Member]
Range of Award		25.00%
Equity-based Performance Stock Units Granted in 2018 [Member] | Maximum [Member]
Range of Award		200.00%
Equity-based Performance Stock Units Granted in 2017 [Member]
Performance Criteria Period (Year)			3 years
Equity-based Performance Stock Units Granted in 2017 [Member] | Minimum [Member]
Range of Award			25.00%
Equity-based Performance Stock Units Granted in 2017 [Member] | Maximum [Member]
Range of Award			200.00%
Equity-based Performance Stock Units Granted in 2016 [Member]
Performance Criteria Period (Year)				3 years
Equity-based Performance Stock Units Granted in 2016 [Member] | Minimum [Member]
Range of Award				25.00%
Equity-based Performance Stock Units Granted in 2016 [Member] | Maximum [Member]
Range of Award				200.00%