Note 3 - Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Net sales	$ 277,524	$ 230,447	$ 507,554	$ 451,962
Grocery [Member]
Net sales	186,171	157,802	344,106	309,103
Dietary Supplements [Member]
Net sales	63,969	49,700	111,870	95,484
Manufactured Product, Other [Member]
Net sales	$ 27,384	$ 22,945	$ 51,578	$ 47,375