Reconciliation of Weighted Average Shares Used in Calculating Basic and Diluted Earnings Per Share (Detail) - shares shares in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Earnings Per Share Disclosure [Line Items]
Basic	48,310	47,991	48,238	48,682
Effect of assuming vesting of performance related to restricted stock-based awards		381		127
Effect of convertible notes subject to conversion		5,753	783	5,411
Effect of convertible notes warrants subject to conversion		1,958		1,681
Diluted	48,310	58,457	50,486	58,306
Stock Options
Earnings Per Share Disclosure [Line Items]
Effect of exercise of stock options		987	77	1,036
Restricted Stock
Earnings Per Share Disclosure [Line Items]
Effect of exercise of stock options		1,387	1,388	1,369

Earnings Per Share Disclosure [Line Items]

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Incremental common shares attributable to performance shares.

+ References

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- Definition

Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of call options and warrants using the treasury stock method.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 23
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=7655603&loc=d3e1757-109256

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Treasury Stock Method
-URI http://asc.fasb.org/extlink&oid=6527216

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Call Option
-URI http://asc.fasb.org/extlink&oid=6506649

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-Publisher FASB
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Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Warrant
-URI http://asc.fasb.org/extlink&oid=6528364

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of convertible debt securities using the if-converted method.

+ References

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- Definition

Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

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- Definition

The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

+ References

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Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

+ References

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