Supplemental Cash Flow Information - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Apr. 30, 2015	Apr. 30, 2014
Disclosure Supplemental Cash Flow Information Additional Information [Abstract]
Interest	$ 5,592us-gaap_InterestPaid	$ 5,514us-gaap_InterestPaid
Income taxes	$ 3,845us-gaap_IncomeTaxesPaidNet	$ 3,496us-gaap_IncomeTaxesPaidNet

The amount of cash paid for interest during the period.

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

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 25

-Subparagraph (e)

-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3536-108585

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