Segments - Reconciliation of Net Income to Adjusted EBITDA (Details) - USD ($) $ in Thousands	3 Months Ended
	Jul. 31, 2018	Jul. 31, 2017
Segments
Net income	$ 8,650	$ 15,343
Interest expense	16,188	7,500
Write-off of debt discount and deferred financing fees		74
Interest income	(236)	(23)
Income tax expense	2,836	10,060
Depreciation expense	10,610	5,990
Amortization expense	15,712	10,355
Stock appreciation expense	334	590
Redeemable noncontrolling interests	531	866
Equity-based compensation	404	473
Severance and other permitted costs	4,836	205
Transaction costs (acquisitions and other)	4,753	159
Gain on sale of assets	(121)	(390)
Effects of fair value adjustments to inventory	4,129
Change in fair value of financial instruments	6,019	196
Secondary public offering costs		631
Debt transaction costs	627	723
Adjusted EBITDA	$ 75,272	$ 52,752