Supplemental Cash Flow Information - Additional Cash Flow Information (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended
Jan. 31, 2014	Jan. 31, 2013
Additional Cash Flow Elements and Supplemental Cash Flow Information [Abstract]
Cash interest paid	$ 82,135	$ 60,924
Cash taxes paid	22,458	24,137
Assets acquired through non-cash capital leases	$ 56,963	$ 27,613

The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income, net of any cash received during the current period as refunds for the overpayment of taxes.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4297-108586

Name:	us-gaap_IncomeTaxesPaidNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration