Capital Stock - Details Regarding Outstanding and Exercisable Stock Options (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2012
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of Outstanding Options	5,285
Outstanding Options, Weighted-Average Remaining Life (Years)	5 years
Outstanding Options, Weighted-Average Exercise Price	$ 34.40
Number of Exercisable Options	4,562
Exercisable Options, Weighted-Average Remaining Life (Years)	4 years 4 months 24 days
Exercisable Options, Weighted Average Exercise Price	$ 35.54
$10.00 - $14.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, lower limit	$ 10.00
Range of Exercise Prices, upper limit	$ 14.99
Number of Outstanding Options	689
Outstanding Options, Weighted-Average Remaining Life (Years)	6 years 2 months 12 days
Outstanding Options, Weighted-Average Exercise Price	$ 11.84
Number of Exercisable Options	689
Exercisable Options, Weighted-Average Remaining Life (Years)	6 years 2 months 12 days
Exercisable Options, Weighted Average Exercise Price	$ 11.84
$15.00 - $19.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, lower limit	$ 15.00
Range of Exercise Prices, upper limit	$ 19.99
Number of Outstanding Options	107
Outstanding Options, Weighted-Average Remaining Life (Years)	2 months 12 days
Outstanding Options, Weighted-Average Exercise Price	$ 19.59
Number of Exercisable Options	107
Exercisable Options, Weighted-Average Remaining Life (Years)	2 months 12 days
Exercisable Options, Weighted Average Exercise Price	$ 19.59
$20.00 - $24.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, lower limit	$ 20.00
Range of Exercise Prices, upper limit	$ 24.99
Number of Outstanding Options	626
Outstanding Options, Weighted-Average Remaining Life (Years)	7 years 1 month 6 days
Outstanding Options, Weighted-Average Exercise Price	$ 24.39
Number of Exercisable Options	392
Exercisable Options, Weighted-Average Remaining Life (Years)	7 years 1 month 6 days
Exercisable Options, Weighted Average Exercise Price	$ 24.37
$25.00 - $29.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, lower limit	$ 25.00
Range of Exercise Prices, upper limit	$ 29.99
Number of Outstanding Options	433
Outstanding Options, Weighted-Average Remaining Life (Years)	9 years 2 months 12 days
Outstanding Options, Weighted-Average Exercise Price	$ 27.69
$30.00 - $34.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, lower limit	$ 30.00
Range of Exercise Prices, upper limit	$ 34.99
Number of Outstanding Options	429
Outstanding Options, Weighted-Average Remaining Life (Years)	2 years 7 months 6 days
Outstanding Options, Weighted-Average Exercise Price	$ 33.84
Number of Exercisable Options	373
Exercisable Options, Weighted-Average Remaining Life (Years)	1 year 9 months 18 days
Exercisable Options, Weighted Average Exercise Price	$ 33.67
$35.00 - $39.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, lower limit	$ 35.00
Range of Exercise Prices, upper limit	$ 39.99
Number of Outstanding Options	741
Outstanding Options, Weighted-Average Remaining Life (Years)	3 years 3 months 18 days
Outstanding Options, Weighted-Average Exercise Price	$ 38.98
Number of Exercisable Options	741
Exercisable Options, Weighted-Average Remaining Life (Years)	3 years 3 months 18 days
Exercisable Options, Weighted Average Exercise Price	$ 38.98
$40.00 - $44.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, lower limit	$ 40.00
Range of Exercise Prices, upper limit	$ 44.99
Number of Outstanding Options	1,246
Outstanding Options, Weighted-Average Remaining Life (Years)	5 years 2 months 12 days
Outstanding Options, Weighted-Average Exercise Price	$ 40.41
Number of Exercisable Options	1,246
Exercisable Options, Weighted-Average Remaining Life (Years)	5 years 2 months 12 days
Exercisable Options, Weighted Average Exercise Price	$ 40.41
$45.00 - $49.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, lower limit	$ 45.00
Range of Exercise Prices, upper limit	$ 49.99
Number of Outstanding Options	345
Outstanding Options, Weighted-Average Remaining Life (Years)	2 years 2 months 12 days
Outstanding Options, Weighted-Average Exercise Price	$ 46.80
Number of Exercisable Options	345
Exercisable Options, Weighted-Average Remaining Life (Years)	2 years 2 months 12 days
Exercisable Options, Weighted Average Exercise Price	$ 46.80
$50.00 - $59.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, lower limit	$ 50.00
Range of Exercise Prices, upper limit	$ 59.99
Number of Outstanding Options	666
Outstanding Options, Weighted-Average Remaining Life (Years)	4 years 2 months 12 days
Outstanding Options, Weighted-Average Exercise Price	$ 51.40
Number of Exercisable Options	666
Exercisable Options, Weighted-Average Remaining Life (Years)	4 years 2 months 12 days
Exercisable Options, Weighted Average Exercise Price	$ 51.40
$60.00 - $64.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, lower limit	$ 60.00
Range of Exercise Prices, upper limit	$ 64.99
Number of Outstanding Options	3
Outstanding Options, Weighted-Average Remaining Life (Years)	4 years 3 months 18 days
Outstanding Options, Weighted-Average Exercise Price	$ 60.96
Number of Exercisable Options	3
Exercisable Options, Weighted-Average Remaining Life (Years)	4 years 3 months 18 days
Exercisable Options, Weighted Average Exercise Price	$ 60.96

Weighted average exercise price as of the balance sheet date for those equity-based payment arrangements exercisable and outstanding.

Name:	us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Weighted average remaining contractual term of exercisable stock options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

+ Details

Name:	us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageRemainingContractualTerm2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The floor of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph 64

-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 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (g)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of shares reserved for issuance pertaining to the outstanding exercisable stock options as of the balance sheet date in the customized range of exercise prices for which the market and performance vesting condition has been satisfied.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(1)(c)

-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 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(iii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of shares reserved for issuance pertaining to the outstanding stock options as of the balance sheet date for all option plans in the customized range of exercise prices.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(i)-(ii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(1)(a, b)

-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

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The weighted average price as of the balance sheet date at which grantees could acquire the underlying shares with respect to all outstanding stock options which are in the customized range of exercise prices.

+ References

+ Details

Name:	us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageExercisePriceBeginningBalance1
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Weighted average remaining contractual term of outstanding stock options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

+ Details

Name:	us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeOutstandingOptionsWeightedAverageRemainingContractualTerm2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The ceiling of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

+ Details

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration