v2.4.0.6

Stock Option Plans (Tables) | 12 Months Ended
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Dec. 31, 2011
Disclosure of Compensation Related Costs, Share-based Payments [Abstract] |
Disclosure of Share-based Compensation Arrangements by Share-based Payment Award | The following table summarizes the Company’s stock option activity for the years ended December 31, 2011 and 2010:
| December 31, 2011 |  | December 31, 2010
| Number of Shares |  | Weighted Average Exercise Price |  | Number of Shares |  | Weighted Average Exercise Price
Outstanding at beginning of period | 1,581 |  |  | $ | 11.68 |  |  | 1,491 |  |  | $ | 10.39 |
Granted | 150 |  |  | 36.75 |  |  | 250 |  |  | 17.27 |
Exercised | (724 | ) |  | 9.72 |  |  | (143 | ) |  | 7.42 |
Expired or forfeited | (29 | ) |  | 21.27 |  |  | (17 | ) |  | 17.35 |
Outstanding at end of period | 978 |  |  | $ | 16.69 |  |  | 1,581 |  |  | $ | 11.68 |
Exercisable at end of year* | 563 |  |  | $ | 11.72 |  |  | 1,118 |  |  | $ | 9.46 |
Participants at end of year | 73 |  |  |  |  | 65 |  |  |
Available for future grants at end of year | 533 |  |  |  |  | 795 |  |  |
_______________ * Remaining contractual term of 7.0 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value | Weighted average grant date fair values of stock options and the assumptions used in estimating the fair values are as follows:
| 2011 |  | 2010 |  | 2009
Weighted average grant date fair value | $ | 24.33 |  |  | $ | 12.03 |  |  | $ | 11.02 |
Expected term (years) | 6.25 |  |  | 6.25 |  |  | 6.25 |
Risk-free interest rate | 2.43 | % |  | 2.46 | % |  | 2.07 | %
Expected volatility | 72.47 | % |  | 77.84 | % |  | 74.87 | %

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- Definition Tabular disclosure of components of a stock option or other award plan under which equity-based compensation is awarded to employees, typically comprised of the amount of unearned compensation (deferred compensation cost), compensation expense, and changes in the quantity and fair value of the shares (or other type of equity) granted, exercised, forfeited, and issued and outstanding pertaining to that plan. Disclosure may also include nature and general terms of such arrangements that existed during the period and potential effects of those arrangements on shareholders, effect of compensation cost arising from equity-based payment arrangements on the income statement, method of estimating the fair value of the goods or services received, or the fair value of the equity instruments granted, during the period, cash flow effects resulting from equity-based payment arrangements and, for registrants that accelerate vesting of out of the money share options, reasons for the decision to accelerate. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph 64, 65, A240 -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 1 -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 -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Tabular disclosure of the weighted-average grant-date fair value of equity options or other equity instruments granted during the year. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Topic 718 -SubTopic 10 -Publisher FASB -Number -Article -Subparagraph (d)(1) -Name Accounting Standards Codification -Paragraph 2 -Section 50 -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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