Segments - Reconciliation of Net Income to Adjusted EBITDA (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2019	Jan. 31, 2018
Segments
Net income	$ 5,815	$ 19,686	$ 39,377	$ 53,052
Interest expense	19,526	7,871	54,896	23,288
Write-off of debt discount and deferred financing fees				74
Interest income	(10)	(44)	(43)	(93)
Provision (benefit) for income taxes	1,442	(4,488)	12,337	15,555
Depreciation expense	11,919	6,009	34,067	18,021
Amortization expense	18,301	10,481	53,262	31,527
Stock appreciation expense	442	631	1,425	1,863
Redeemable noncontrolling interests	(35)	340	778	1,370
Equity-based compensation	1,140	430	2,638	1,277
Severance and other permitted costs	229	8	5,947	325
Transaction costs (acquisitions and other)	1,066	75	6,660	321
Gain on sale of assets	(118)	(51)	(412)	(648)
Effects of fair value adjustments to inventory		89	4,129	276
Change in fair value of financial instruments		276	6,395	710
Secondary public offering costs		894		1,525
Debt transaction costs			678	758
Adjusted EBITDA	$ 59,717	$ 42,207	$ 222,134	$ 149,201