Basis of Presentation, Business and Summary of Significant Accounting Policies - Deferred Financing Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2017	Apr. 30, 2016	Apr. 30, 2015
Debt and financing costs
Lender and third party deferred financing costs reported as a reduction of Term Loan Facilities	$ 5,712	$ 11,147
Lender and third party deferred financing costs related to ABL Facility	2,950	2,544
Write-off of debt discount and deferred financing fees	7,103
Interest expense
Debt and financing costs
Amortization of deferred financing costs	$ 2,247	$ 2,961	$ 2,907