Goodwill and Intangible Assets - Components of Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	Apr. 30, 2014	Apr. 30, 2013
Finite-Lived Intangible Assets [Line Items]
Intangible assets	$ 33,005	$ 28,703
Less accumulated amortization	(19,585)	(17,029)
Intangible assets, net	13,420	11,674
Covenants Not- to- Compete [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets	17,245	17,043
Less accumulated amortization	(15,363)	(14,800)
Intangible assets, net	1,882	2,243
Client Lists [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets	15,760	11,660
Less accumulated amortization	(4,222)	(2,229)
Intangible assets, net	$ 11,538	$ 9,431

Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16323-109275

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- Definition

Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

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- Definition

Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

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