Segments - Reconciliation of Net Income to Adjusted EBITDA (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2019	Oct. 31, 2018
Segments
Net income	$ 29,138	$ 24,912	$ 53,958	$ 33,562
Interest expense	17,559	19,182	35,836	35,370
Write-off of debt discount and deferred financing fees	707		707
Interest income	(6)	203	(18)	(33)
Provision for income taxes	7,927	8,059	15,517	10,895
Depreciation expense	12,592	11,538	25,014	22,148
Amortization expense	16,926	19,249	33,779	34,961
Stock appreciation expense	1,267	649	1,327	983
Redeemable noncontrolling interests	(18)	282	644	813
Equity-based compensation	2,315	1,094	3,710	1,498
Severance and other permitted costs	1,394	882	1,948	5,718
Transaction costs (acquisitions and other)	327	841	1,299	5,594
Gain on sale of assets	(586)	(173)	(742)	(294)
Effects of fair value adjustments to inventory			151	4,129
Change in fair value of financial instruments		376		6,395
Secondary public offering costs	363		363
Debt transaction costs		51		678
Adjusted EBITDA	$ 89,905	$ 87,145	$ 173,493	$ 162,417