Segments - Reconciliation of Net Income to Adjusted EBITDA (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2018	Oct. 31, 2017
Segments
Net income	$ 24,912	$ 18,023	$ 33,562	$ 33,366
Interest expense	19,182	7,917	35,370	15,417
Write-off of debt discount and deferred financing fees				74
Interest income	203	(26)	(33)	(49)
Income tax expense	8,059	9,983	10,895	20,043
Depreciation expense	11,538	6,023	22,148	12,013
Amortization expense	19,249	10,690	34,961	21,045
Stock appreciation expense	649	642	983	1,232
Redeemable noncontrolling interests	282	164	813	1,030
Equity-based compensation	1,094	375	1,498	847
Severance and other permitted costs	882	113	5,718	317
Transaction costs (acquisitions and other)	841	88	5,594	246
Gain on sale of assets	(173)	(207)	(294)	(597)
Effects of fair value adjustments to inventory		187	4,129	187
Change in fair value of financial instruments	376	238	6,395	434
Secondary public offering costs				631
Debt transaction costs	51	35	678	758
Adjusted EBITDA	$ 87,145	$ 54,245	$ 162,417	$ 106,994