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Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions | 12 Months Ended
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Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number | 2.5 |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price | $ 10.54 |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Number | 0.9 |  |
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost | $ 4.8 | $ 6.7 | $ 6.1
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense | $ 2.2 | $ 2.2 | $ 1.6
Exercisable at end of year (shares) | 1.6 | 1.4 | 1.2
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Aggregate Intrinsic Value | $ 12.9 |  |
Shares authorized under stock compensation plans | 7.8 |  |
Shares authorized under stock compensation plans | Apr. 30, 2025 |  |
Stock options vesting period | 3 years |  |
Weighted average fair value of options granted (usd per share) | $ 4.25 | $ 6.12 | $ 7.16
Aggregate intrinsic value of stock options outstanding | $ 10.8 |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value | 0.4 | $ 0.8 | $ 2.0
Proceeds from stock compensation activity | 0.5 | 1.0 | $ 2.6
Percentage of target shares earned |  |  | 200.00%
Excess tax benefit from stock-based compensation | 0.0 | 1.6 | $ 2.2
Employee Service Share-based Compensation, Tax Benefit Realized from Exercise of Stock Options | 0.1 | 0.2 | 0.8
Restricted Stock |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value | 1.3 | 1.3 | 0.6
Compensation expense related to share-based compensation plans | 1.2 | 1.2 | 1.0
Unrecognized compensation cost related to stock options | $ 0.8 |  |
Weighted-average recognition period for unrecognized compensation cost | 1 year 10 months 28 days |  |
Stock Options |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Compensation expense related to share-based compensation plans | $ 2.1 | 2.0 | 1.7
Unrecognized compensation cost related to stock options | $ 2.8 |  |
Weighted-average recognition period for unrecognized compensation cost | 1 year 10 months 28 days |  |
PSUs [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value | $ 3.7 | 3.7 | 2.5
Compensation expense related to share-based compensation plans | 1.5 | $ 3.5 | $ 3.4
Unrecognized compensation cost | $ 1.1 |  |
Weighted-average recognition period for unrecognized compensation cost | 2 years |  |
Minimum | PSUs [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Purchase price of common stock, percent | 0.00% |  |
Maximum | PSUs [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Purchase price of common stock, percent | 200.00% |  |
2013 Grants | PSUs [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Stock options vesting period | 3 years |  |
2014 Grants | PSUs [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Stock options vesting period | 3 years |  |
Performance share units performance period | 2 years |  |
Service requirement | 1 year |  |
Percentage of target shares earned | 200.00% |  |
2015 Grants | PSUs [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Stock options vesting period | 3 years |  |
Performance-based Restricted Stock Units, 2016 Grants [Member] | PSUs [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Performance share units performance period | 3 years |  |

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- Definition Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 14.F) -URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5047-113901 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(1)(i) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income 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 (h)(1)(i) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Disclosure of the aggregate tax benefit realized from the exercise of stock options and the conversion of similar instruments during the annual 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 (j) -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 The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested). + 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)(3) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan. + 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)(iii) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology. + 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)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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