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Compensation Plans (Details) (USD $) | 3 Months Ended
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Mar. 31, 2014 | Mar. 31, 2013
RSUs, PSUs, and Director's Shares [Abstract] |  |
Stock-based compensation expense | $ 6,344,000 | $ 8,113,000
Cash Bonus Plan [Member] |  |
Compensation plans |  |
Accrued Cash Bonus Plan Expense | 6,600,000 | 5,600,000
Restricted Stock Units (RSUs) [Member] |  |
RSUs, PSUs, and Director's Shares [Abstract] |  |
Number of Common Shares to be Received Upon Settlement | 1 |
Stock-based compensation expense | 2,800,000 | 3,000,000
Unrecognized stock based compensation expense | 15,900,000 |
Performance Shares [Member] |  |
RSUs, PSUs, and Director's Shares [Abstract] |  |
Stock-based compensation expense | 3,200,000 | 4,700,000
Unrecognized stock based compensation expense | 14,900,000 |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Low End of Range | 0 |
Common stock awards vesting multiplier, high end of range | 2 |
Share-based Compensation, Awards Other Than Options, Performance Measurement Period | 3 |
Employee Stock Option [Member] |  |
Stock option activity |  |
Stock options outstanding at the end of the period (in shares) | 39,088 |
Weighted-Average Exercise Price |  |
Stock options outstanding at the end of the period (in dollars per share) | $ 20.87 |
Aggregate Intrinsic Value |  |
Vested at the end of the period | $ 1,971,000 |

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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 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5047-113901 Reference 2: 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 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 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 14 -Section F + Details
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