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Share-based Compensation - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified | 9 Months Ended
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Sep. 30, 2013 OptionPlan | Sep. 30, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Number of inactive stock option plans | 1 |
Number of active stock incentive plans | 1 |
Unrecognized compensation expense | $ 4.9 |
Expected period of compensation expense recognition | 1 year 10 months 24 days |
Total intrinsic value | $ 0.1 |
RSUs and PSAs at target level of performance included in unvested balance | 198,000 |
Minimum performance awards issued multiplier | 0.00% |
Maximum performance awards issued multiplier | 200.00% |
Fair market value of stock awards used in calculation of compensation expense, grant date | $ 27.49 | $ 23.40
Restricted Stock Units and Performance Awards [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Vesting period of PSAs | 3 years |
Minimum [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Vesting period of PSAs | 2 years |
Maximum [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Vesting period of PSAs | 3 years |
Director [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Stock awards granted to non-employee directors | 4,912 | 4,807

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- Definition Minimum performance awards issued multiplier. + References No definition available. + Details
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- Definition Number of active stock incentive plans. + References No definition available. + Details
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- Definition Number of inactive stock option plans. + References No definition available. + Details
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- Definition The number of non-vested equity-based payment instruments at a target level of performance, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date. + References No definition available. + Details
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- Definition Share based compensation arrangement by stock based payment award grant date fair value. + References No definition available. + Details
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- Definition Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + 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 (i) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Unrecognized cost of unvested share-based awards, other than options, awarded to employees as compensation. + References No definition available. + Details
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- Definition Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + 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 (a)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Details
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- Definition Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares. + 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 (d)(2) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The number of shares or units of entity securities issued in the transaction in which equity securities were issued to pay for goods or nonemployee services. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 50 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6406099&loc=d3e25284-112666 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)(1)(iv)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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