Integration and Restructuring Costs - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Apr. 30, 2020	Apr. 30, 2019	Apr. 30, 2018
Ainsworth [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred noncash charge	$ 0.6	$ 4.1
Restructuring and related cost, noncash charge incurred to date	4.7
Restructuring and related cost, incurred cost	16.5	32.1
Total costs incurred to date	48.6
Restructuring and related cost obligations	0.5	1.6
Ainsworth [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred cost	2.4	15.5
Total costs incurred to date	17.9
Ainsworth [Member] | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred cost	14.1	16.6
Total costs incurred to date	30.7
Big Heart [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred noncash charge			$ 2.6
Restructuring and related cost, incurred cost	0.0	0.0	26.6
Big Heart [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost obligations		0.0
Organization Optimization Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, incurred noncash charge		3.3	9.8
Restructuring and related cost, noncash charge incurred to date		15.2
Restructuring and related cost, incurred cost	0.0	32.0	$ 22.7
Total costs incurred to date		74.6
Restructuring and related cost obligations	$ 0.0	0.8
Organization Optimization Program [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Total costs incurred to date		48.7
Organization Optimization Program [Member] | Other Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Total costs incurred to date		$ 25.9