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Share-Based Compensation Plans - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified | 12 Months Ended
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Dec. 31, 2013 OptionPlan | Dec. 31, 2012 | Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Number of inactive stock option plan | 1 |  |
Number of active stock incentive plan | 1 |  |
Maximum duration over which awards become exercisable under the plan | 60 months |  |
Termination date of the option from date of grant, in years | 10 years |  |
Number of common stock shares available for future issuance | 720,301 | 227,177 | 307,984
Restricted stock units and performance stock awards granted and remain outstanding |  |  |
Total intrinsic value of options exercised | $ 0.1 | $ 0.1 | $ 0.8
Number of options granted | 0 | 0 | 0
RSUs and PSAs at target level of performance included in unvested balance | 196,000 |  |
Minimum performance awards issued multiplier | 0.00% |  |
Maximum performance awards issued multiplier | 200.00% |  |
Directors [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Stock awards granted to non-employee directors | 4,912 | 4,807 | 6,261
Grant date fair market value of stock awards | $ 27.49 | $ 23.40 | $ 25.15
Restricted Stock Units and Performance Stock Awards [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Maximum duration over which awards become exercisable under the plan | 3 years |  |
Unrecognized compensation expense | 3.9 |  |
Expected period of compensation expense recognized | 1 year 9 months 18 days |  |
Restricted stock units and performance stock awards granted and remain outstanding | 40,000 |  |
Restricted stock units and performance stock awards granted and remain outstanding | 257,087 |  |
Fair value of RSUs and PSAs vested | $ 2.1 | $ 0.6 | $ 0.4
Performance Shares [Member] | Minimum [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Maximum duration over which awards become exercisable under the plan | 2 years |  |
Performance Shares [Member] | Maximum [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Maximum duration over which awards become exercisable under the plan | 3 years |  |

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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 share based payment award options award expiration period. + 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 Aggregate number of common shares reserved for future issuance. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.29) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + 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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- Definition Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash. + 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 Net number of non-option equity instruments granted to participants. + 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)(iv)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + 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 Net number of share options (or share units) granted during the period. + 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)(iv)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Gross number of share options (or share units) granted during the period. + References No definition available. + 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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