Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2016
Cash flows from operating activities:
Net income	$ 62,971	$ 48,886	$ 12,564
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	65,530	69,240	64,215
Write-off and amortization of debt discount and debt issuance costs	2,851	9,793	3,438
Provision for losses on accounts and notes receivable	(622)	(122)	(1,032)
Provision for obsolescence of inventory	106	425	80
Increase (decrease) in fair value of contingent consideration	195	(1,484)
Equity-based compensation	5,745	3,142	4,733
Gain on sale and disposal of assets	(509)	(336)	(645)
Change in fair value of financial instruments	6,125
Changes in assets and liabilities net of effects of acquisitions:
Trade accounts and notes receivable	(11,752)	(20,400)	(27,338)
Inventories	(34,774)	(18,390)	(699)
Prepaid expenses and other assets	(1,926)	(412)	(4,682)
Accounts payable	11,365	(3,763)	1,055
Accrued compensation and employee benefits	(236)	4,440	3,454
Other accrued expenses and current liabilities	4,874	626	5,551
Deferred income taxes	(16,224)	(20,114)	(20,499)
Liabilities to noncontrolling interest holders	(3,704)	1,133	446
Income tax receivable / payable	(1,399)	(5,956)	7,106
Cash provided by operating activities	88,616	66,708	47,747
Cash flows from investing activities:
Purchases of property and equipment	(23,741)	(11,083)	(7,692)
Proceeds from sale of assets	2,865	3,995	9,847
Acquisition of businesses, net of cash acquired	(28,333)	(150,428)	(120,195)
Cash used in investing activities	(49,209)	(157,516)	(118,040)
Cash flows from financing activities:
Repayments on the revolving credit facility	(617,230)	(1,011,925)	(697,144)
Borrowings from the revolving credit facility	513,878	1,013,365	782,104
Payments of principal on long-term debt	(5,776)	(4,584)	(3,931)
Payments of principal on capital lease obligations	(6,132)	(5,208)	(4,249)
Proceeds from issuance of common stock in initial public offering, net of underwriting discounts		156,941
Borrowings from term loan amendments	577,616	481,225
Debt issuance costs	(636)	(2,637)	(391)
Stock repurchases			(5,827)
Payments for taxes related to net share settlement of equity awards	(1,441)
Proceeds from exercises of stock options	477	345	6,519
Other financing activities	(671)
Cash (used in) provided by financing activities	(17,531)	86,297	77,081
Increase (decrease) in cash and cash equivalents	21,876	(4,511)	6,788
Cash and cash equivalents, beginning of year	14,561	19,072	12,284
Cash and cash equivalents, end of year	36,437	14,561	19,072
Supplemental cash flow disclosures:
Cash paid for income taxes	38,954	49,163	26,067
Cash paid for interest	28,613	26,443	34,557
Supplemental schedule of noncash activities:
Assets acquired under capital lease	9,086	9,410	7,542
Issuance of installment notes associated with equity-based compensation liability awards	12,433	5,352	1,557
Increase in other liabilities due to transition guidance			3,208
(Decrease) increase in insurance claims payable and insurance recoverable	(2,362)	1,876	$ (25,715)
Second Lien Term Loan
Cash flows from financing activities:
Repayment of term loan / Repayment of term loan amendments		(160,000)
Second amendment to First Lien Credit Agreement
Cash flows from financing activities:
Repayment of term loan / Repayment of term loan amendments	$ (477,616)	$ (381,225)