Carrying amount as of the balance sheet date, which is the cumulative amount paid and (if applicable) the fair value of any noncontrolling interest in the acquiree, adjusted for any amortization recognized prior to the adoption of any changes in generally accepted accounting principles (as applicable) and for any impairment charges, in excess of the fair value of net assets acquired in one or more business combination transactions.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 142

-Paragraph 45

-Subparagraph e

-Clause 1

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=14024403&loc=d3e13816-109267

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141R

-Paragraph 68

-Subparagraph l

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141R

-Paragraph 34

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 142

-Paragraph 43

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 142

-Paragraph 45

-Subparagraph e

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141R

-Paragraph 72

-Subparagraph d

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

- Definition

Amount, net of accumulated depreciation, depletion and amortization, of long-lived physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

+ References+ Details

Property and Equipment and Goodwill by Geographic Area (Detail) (USD $) In Thousands, unless otherwise specified	Jan. 31, 2013	Apr. 30, 2012	Apr. 30, 2011	Apr. 30, 2010
Segment Reporting, Other Significant Reconciling Item [Line Items]
Property and equipment	$ 1,186,376	$ 1,026,860	$ 1,133,499
Goodwill	437,359	433,811	448,121	425,514
CANADA
Segment Reporting, Other Significant Reconciling Item [Line Items]
Property and equipment		62,425	91,779
Goodwill		10,857	11,149
UNITED KINGDOM
Segment Reporting, Other Significant Reconciling Item [Line Items]
Property and equipment		60,323	75,879
Goodwill		87,800	93,087
NORWAY
Segment Reporting, Other Significant Reconciling Item [Line Items]
Property and equipment		525,470	532,338
Goodwill		39,716	43,526
Africa
Segment Reporting, Other Significant Reconciling Item [Line Items]
Property and equipment		55,247	95,138
Goodwill		9,794	10,470
AUSTRALIA
Segment Reporting, Other Significant Reconciling Item [Line Items]
Property and equipment		111,920	97,954
Goodwill		19,523	20,425
DENMARK
Segment Reporting, Other Significant Reconciling Item [Line Items]
Property and equipment		685	744
Goodwill		1,076	1,199
NETHERLANDS
Segment Reporting, Other Significant Reconciling Item [Line Items]
Property and equipment		9,450	19,466
Goodwill		36,179	40,446
Asia
Segment Reporting, Other Significant Reconciling Item [Line Items]
Property and equipment		43,084	46,035
Goodwill		16,100	16,100
Other European Countries
Segment Reporting, Other Significant Reconciling Item [Line Items]
Property and equipment		58,852	58,686
Goodwill		7,045	7,873
Other Countries
Segment Reporting, Other Significant Reconciling Item [Line Items]
Property and equipment		99,404	115,480
Goodwill		$ 205,721	$ 203,846