Schedule of Stock Compensation Plan Activity (Detail) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award
Awarded	1,844	1,936	2,626
Forfeited	(204)	(435)	(153)
Outstanding at January 1	5,335	7,194	11,238
Granted	151	145	329
Assumed from acquisition		2,828
Exercised	(1,396)	(965)	(4,031)
Forfeited	(203)
Cancelled	(46)	(3,867)	(342)
Outstanding at December 31	3,841	5,335	7,194
Vested and expected to vest at December 31	3,785	4,904	7,193
Exercisable at December 31	2,004	1,844	6,046
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award
Non-vested at January 1	5,840	6,963	6,896
Awarded	1,844	1,936	2,626
Vested	(2,510)	(2,624)	(2,406)
Forfeited	(204)	(435)	(153)
Non-vested at December 31	4,970	5,840	6,963

Share Based Compensation Arrangement By Share Based Payment Award Options Assumed From Acquisitions In Period

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- Definition

Share Based Compensation Arrangement By Share Based Payment Award Options Cancelled In Period

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No definition available.

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- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

+ References

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

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- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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- Definition

The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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Net number of share options (or share units) granted during the period.

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- Definition

The number of shares reserved for issuance under stock option agreements awarded under the plan that validly exist and are outstanding as of the balance sheet date, including vested options.

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The number of exercisable share options (fully vested and expected to vest) that may be converted as of the balance sheet date.

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As of the balance sheet date, the number of shares into which fully vested and expected to vest stock options outstanding can be converted under the option plan.

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Number of share options (or share units) exercised during the current period.

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