<?xml version="1.0" encoding="us-ascii"?><InstanceReport xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><Version>2.4.0.8</Version><ReportLongName>2110100 - Disclosure - Stock-Based Compensation Plans</ReportLongName><DisplayLabelColumn>true</DisplayLabelColumn><ShowElementNames>false</ShowElementNames><RoundingOption /><HasEmbeddedReports>false</HasEmbeddedReports><Columns><Column FlagID="0"><Id>1</Id><IsAbstractGroupTitle>false</IsAbstractGroupTitle><LabelSeparator>

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</LabelSeparator><Level>1</Level><ElementName>us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract</ElementName><ElementPrefix>us-gaap_</ElementPrefix><IsBaseElement>true</IsBaseElement><BalanceType>na</BalanceType><PeriodType>duration</PeriodType><IsReportTitle>false</IsReportTitle><IsSegmentTitle>false</IsSegmentTitle><IsCalendarTitle>false</IsCalendarTitle><IsEquityPrevioslyReportedAsRow>false</IsEquityPrevioslyReportedAsRow><IsEquityAdjustmentRow>false</IsEquityAdjustmentRow><IsBeginningBalance>false</IsBeginningBalance><IsEndingBalance>false</IsEndingBalance><IsReverseSign>false</IsReverseSign><FootnoteIndexer /><Cells><Cell FlagID="0" ContextID="" UnitID=""><Id>1</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText /><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat></Cell></Cells><ElementDataType>xbrli:stringItemType</ElementDataType><SimpleDataType>string</SimpleDataType><IsTotalLabel>false</IsTotalLabel><UnitID>0</UnitID><Label>Disclosure of Compensation Related Costs, Share-based Payments [Abstract]</Label></Row><Row FlagID="0"><Id>2</Id><IsAbstractGroupTitle>false</IsAbstractGroupTitle><LabelSeparator>

</LabelSeparator><Level>2</Level><ElementName>us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock</ElementName><ElementPrefix>us-gaap_</ElementPrefix><IsBaseElement>true</IsBaseElement><BalanceType>na</BalanceType><PeriodType>duration</PeriodType><IsReportTitle>false</IsReportTitle><IsSegmentTitle>false</IsSegmentTitle><IsCalendarTitle>false</IsCalendarTitle><IsEquityPrevioslyReportedAsRow>false</IsEquityPrevioslyReportedAsRow><IsEquityAdjustmentRow>false</IsEquityAdjustmentRow><IsBeginningBalance>false</IsBeginningBalance><IsEndingBalance>false</IsEndingBalance><IsReverseSign>false</IsReverseSign><PreferredLabelRole>verboseLabel</PreferredLabelRole><FootnoteIndexer /><Cells><Cell FlagID="0" ContextID="D2013Q2YTD" UnitID=""><Id>1</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText>&lt;div style="font-family:Times New Roman;font-size:10pt;"&gt;&lt;div style="line-height:120%;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;font-weight:bold;"&gt;STOCK-BASED COMPENSATION PLANS&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; &lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-bottom:8px;padding-top:4px;text-indent:36px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;The Company provides stock-based compensation benefits to employees and non-employee directors pursuant to its 2007 Long Term Incentive Plan, as amended ("the Incentive Plan"), as well as to employees pursuant to its Employee Stock Purchase Plan (the "Purchase Plan"), as amended.&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-bottom:8px;padding-top:4px;text-indent:36px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;font-style:italic;font-weight:bold;"&gt;2007 Long Term Incentive Plan&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-bottom:8px;padding-top:4px;text-indent:36px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;The Incentive Plan provides for the issuance up to &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;7.5 million&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; shares for grants to non-employee directors, officers and other employees of the Company and its subsidiaries of: (a)&amp;#160;options (including options qualified as incentive stock options under the Internal Revenue Code of 1986 and options that are non-qualified), the exercise price of which may not be less than the fair market value of the common stock on the date of the grant; and (b)&amp;#160;stock appreciation rights, restricted stock, performance awards, and bonus stock, each granted at the market price of the Company&amp;#8217;s common stock at the date of grant. The Incentive Plan expires on &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;March&amp;#160;8, 2017&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;. The terms of the awards (including vesting schedules) are established by the Compensation Committee of the Company&amp;#8217;s Board of Directors. As of &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;June&amp;#160;30, 2013&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;, there were &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;817,174&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&amp;#160;shares available for issuance under the Incentive Plan.&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-bottom:8px;padding-top:4px;text-indent:36px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;In 2005, the Company began granting to non-employee directors and certain employees, at no cost to the recipient, restricted stock awards or, at their election, restricted stock units pursuant to the Incentive Plan. Restricted stock awards qualify as participating securities as each contain non-forfeitable rights to dividends. As such, the two-class method is required for the computation of earnings per share. See Note 5, &amp;#8220;Earnings Per Share,&amp;#8221; for further details. Restricted stock awards are considered outstanding at the date of grant but are subject to vesting periods ranging from six months to five years. Vested restricted stock units, which are not considered outstanding at the grant date, will settle in shares of common stock upon the termination of the grantees&amp;#8217; employment or directorship. In the event an employee or non-employee director terminates his or her employment or directorship with the Company prior to the lapse of the restrictions, the shares, in most cases, will be forfeited to the Company. Compensation expense for these awards is calculated based on the market price of the Company&amp;#8217;s common stock at the date of grant and recognized over the requisite service period. Forfeitures are estimated at the time of valuation and reduce expense ratably over the vesting period. This estimate is adjusted annually based on the extent to which actual or expected forfeitures differ from the previous estimate.&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-bottom:8px;padding-top:4px;text-indent:36px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;A summary of these awards as of &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;June&amp;#160;30, 2013&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;, along with the changes during the six months then ended follows:&lt;/font&gt;&lt;div style="padding-left:0px;text-indent:0px;line-height:normal;padding-top:10px;"&gt;&lt;table cellpadding="0" cellspacing="0" style="font-family:Times New Roman;font-size:10pt;width:99.80506822612085%;border-collapse:collapse;text-align:left;"&gt;&lt;tr&gt;&lt;td colspan="8" rowspan="1"&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td width="64%" rowspan="1" colspan="1"&gt;&lt;/td&gt;&lt;td width="1%" rowspan="1" colspan="1"&gt;&lt;/td&gt;&lt;td width="16%" rowspan="1" colspan="1"&gt;&lt;/td&gt;&lt;td width="1%" rowspan="1" colspan="1"&gt;&lt;/td&gt;&lt;td width="1%" rowspan="1" colspan="1"&gt;&lt;/td&gt;&lt;td width="1%" rowspan="1" colspan="1"&gt;&lt;/td&gt;&lt;td width="15%" rowspan="1" colspan="1"&gt;&lt;/td&gt;&lt;td width="1%" rowspan="1" colspan="1"&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"&gt;&lt;div style="overflow:hidden;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"&gt;&lt;div style="overflow:hidden;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td colspan="2" style="vertical-align:bottom;border-bottom:1px solid #000000;padding-top:2px;padding-bottom:2px;" rowspan="1"&gt;&lt;div style="text-align:center;font-size:8pt;"&gt;&lt;font style="font-family:inherit;font-size:8pt;font-weight:bold;"&gt;Awards&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"&gt;&lt;div style="overflow:hidden;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td colspan="3" style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"&gt;&lt;div style="text-align:center;font-size:8pt;"&gt;&lt;font style="font-family:inherit;font-size:8pt;font-weight:bold;"&gt;Weighted&amp;#160;Average&lt;/font&gt;&lt;/div&gt;&lt;div style="text-align:center;font-size:8pt;"&gt;&lt;font style="font-family:inherit;font-size:8pt;font-weight:bold;"&gt;Grant Date&lt;/font&gt;&lt;/div&gt;&lt;div style="text-align:center;font-size:8pt;"&gt;&lt;font style="font-family:inherit;font-size:8pt;font-weight:bold;"&gt;Fair Value&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td style="vertical-align:top;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"&gt;&lt;div style="font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;Nonvested at December 31, 2012&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"&gt;&lt;div style="overflow:hidden;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;border-top:1px solid #000000;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:right;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;1,023,350&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;background-color:#cceeff;border-top:1px solid #000000;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:left;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&lt;br clear="none"/&gt;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"&gt;&lt;div style="overflow:hidden;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;background-color:#cceeff;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:left;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;$&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;background-color:#cceeff;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:right;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;38.19&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;background-color:#cceeff;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:left;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&lt;br clear="none"/&gt;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td style="vertical-align:top;background-color:;padding-left:28px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:left;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;Granted&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"&gt;&lt;div style="overflow:hidden;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:right;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;261,786&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:left;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&lt;br clear="none"/&gt;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"&gt;&lt;div style="overflow:hidden;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td colspan="2" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1"&gt;&lt;div style="text-align:right;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;59.17&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:left;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&lt;br clear="none"/&gt;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td style="vertical-align:top;background-color:#cceeff;padding-left:28px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:left;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;Vested&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"&gt;&lt;div style="overflow:hidden;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:right;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;(120,300&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;background-color:#cceeff;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:left;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;)&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"&gt;&lt;div style="overflow:hidden;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td colspan="2" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1"&gt;&lt;div style="text-align:right;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;35.84&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;background-color:#cceeff;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:left;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&lt;br clear="none"/&gt;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td style="vertical-align:top;background-color:;padding-left:28px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:left;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;Forfeited&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"&gt;&lt;div style="overflow:hidden;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:right;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;(42,920&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;border-bottom:1px solid #000000;padding-right:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:left;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;)&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"&gt;&lt;div style="overflow:hidden;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td colspan="2" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1"&gt;&lt;div style="text-align:right;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;42.50&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:left;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&lt;br clear="none"/&gt;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td style="vertical-align:top;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"&gt;&lt;div style="font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;Nonvested at June 30, 2013&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"&gt;&lt;div style="overflow:hidden;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:right;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;1,121,916&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;border-bottom:1px solid #000000;background-color:#cceeff;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:left;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&lt;br clear="none"/&gt;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"&gt;&lt;div style="overflow:hidden;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;background-color:#cceeff;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:left;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;$&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;background-color:#cceeff;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:right;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;43.19&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;background-color:#cceeff;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:left;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&lt;br clear="none"/&gt;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;&lt;/table&gt;&lt;/div&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&lt;br clear="none"/&gt;&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-bottom:8px;padding-top:4px;text-indent:24px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;font-style:italic;font-weight:bold;"&gt;Employee Stock Purchase Plan&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-bottom:8px;padding-top:4px;text-indent:36px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;In 1997, the Company adopted the Purchase Plan. The Purchase Plan authorizes the issuance of up to &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;3.5 million&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; shares of common stock and provides that no options to purchase shares may be granted under the Purchase Plan after &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;March 6, 2016&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;. The Purchase Plan is available to all employees of the Company and its participating subsidiaries and is a qualified plan as defined by Section&amp;#160;423 of the Internal Revenue Code. At the end of each fiscal quarter (the &amp;#8220;Option Period&amp;#8221;) during the term of the Purchase Plan, employees can acquire shares of common stock from the Company at &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;85%&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; of the fair market value of the common stock on the first or the last day of the Option Period, whichever is lower. As of &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;June&amp;#160;30, 2013&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;, there were &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;665,734&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&amp;#160;shares available for issuance under the Purchase Plan. During the six months ended &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;June&amp;#160;30, 2013&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; and &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;2012&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;, the Company issued &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;58,525&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; and &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;56,149&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; shares, respectively, of common stock to employees participating in the Purchase Plan.&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-bottom:8px;padding-top:4px;text-indent:36px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;The weighted average fair value of employee stock purchase rights issued pursuant to the Purchase Plan was &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$13.40&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; and &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$11.68&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; during the six months ended &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;June&amp;#160;30, 2013&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; and &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;2012&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;, respectively. The fair value of stock purchase rights is calculated using the grant date stock price,&amp;#160;the value of the embedded call option and&amp;#160;the value of the embedded put option.&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-bottom:8px;padding-top:4px;text-indent:24px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;font-style:italic;font-weight:bold;"&gt;Stock-Based Compensation&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-bottom:8px;padding-top:4px;text-indent:36px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;Total stock-based compensation cost was &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$3.6 million&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; and &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$3.0 million&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; for the three months ended &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;June&amp;#160;30, 2013&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; and &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;2012&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;, respectively, and &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$7.0 million&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; and &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$5.9 million&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; for the six months ended &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;June&amp;#160;30, 2013&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; and &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;2012&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;, respectively. Cash received from Purchase Plan purchases was &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$3.0 million&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; for the six months ended &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;June&amp;#160;30, 2013&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;. Cash received from both option exercises and Purchase Plan purchases was &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$3.1 million&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; for the six months ended &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;June&amp;#160;30, 2012&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;. The tax benefit realized for the tax deductions from the vesting of restricted shares, which increased additional paid in capital, totaled &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$1.1 million&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; for the six months ended &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;June&amp;#160;30, 2013&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;; in addition, the tax benefit realized for the tax deductions from both options exercised and vesting of restricted shares, which increased additional paid in capital, totaled &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$1.6 million&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; for the six months ended &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;June&amp;#160;30, 2012&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;. &lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-bottom:8px;padding-top:4px;text-indent:36px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;The Company issues new shares or treasury shares, if available, when restricted stock vests. 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