Business, Basis of Presentation and Summary of Significant Accounting Policies - Revision of Previously Issued Statements of Cash Flows (Details) - USD ($) $ in Thousands	9 Months Ended
Jan. 31, 2018	Jan. 31, 2017
Cash flows from investing activities:
Acquisition of business, net of cash acquired	$ (23,568)	$ (145,976)
Cash used in investing activities	(34,602)	(149,631)
Cash flows from financing activities:
Cash provided by financing activities	$ (14,753)	104,821
As previously reported
Cash flows from investing activities:
Acquisition of business, net of cash acquired		(141,650)
Cash used in investing activities		(145,305)
Cash flows from financing activities:
Cash paid for contingent consideration		(4,326)
Cash provided by financing activities		100,495
Correction for misstatement of cash flows related to payments of working capital settlements \| Adjustment
Cash flows from investing activities:
Acquisition of business, net of cash acquired		(4,326)
Cash used in investing activities		(4,326)
Cash flows from financing activities:
Cash paid for contingent consideration		4,326
Cash provided by financing activities		$ 4,326

Amount of cash inflow (outflow) from financing activities, including discontinued operations. Financing activity cash flows include obtaining resources from owners and providing them with a return on, and a return of, their investment; borrowing money and repaying amounts borrowed, or settling the obligation; and obtaining and paying for other resources obtained from creditors on long-term credit.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 24
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3521-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 26
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3574-108585

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Amount of cash inflow (outflow) from investing activities, including discontinued operations. Investing activity cash flows include making and collecting loans and acquiring and disposing of debt or equity instruments and property, plant, and equipment and other productive assets.

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Amount of cash outflow, not made soon after acquisition date of business combination, to settle contingent consideration liability up to amount recognized at acquisition date, including, but not limited to, measurement period adjustment and less amount paid soon after acquisition date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3291-108585

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The cash outflow associated with the acquisition of a business, net of the cash acquired from the purchase.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3213-108585

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