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Share-Based Payments (Narrative) (Details) | 12 Months Ended
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Dec. 31, 2015 USD ($) Award_Type | Dec. 31, 2014 USD ($) | Dec. 31, 2013 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Number of award types | Award_Type | 3 |  |
The aggregate grant date intrinsic value of options exercised | $ 100,000 | $ 300,000 | $ 100,000
Aggregate intrinsic value of stock options outstanding | $ 100,000 |  |
Weighted average remaining contractual term of stock options | 2 years 2 months 14 days |  |
Cash proceeds from stock option exercises | $ 0 | 0 | 0
Restricted Stock Units (RSUs) [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Expected average period | 3 years |  |
The aggregate grant date fair value | $ 2,100,000 | 1,500,000 | 1,400,000
Aggregate intrinsic value | $ 2,300,000 | 2,300,000 | 2,700,000
Performance Shares Units [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Expected average period | 3 years |  |
The aggregate grant date fair value | $ 7,700,000 | 5,200,000 | 5,100,000
Aggregate intrinsic value | $ 8,400,000 | $ 7,700,000 | $ 9,100,000
The percentage of award vest | 115.00% | 125.00% | 125.00%
Performance Shares Units [Member] | Minimum [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
The percentage of award vest | 75.00% |  |
Performance Shares Units [Member] | Maximum [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
The percentage of award vest | 125.00% |  |
Employee Purchase Plan [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Expected average period | 3 years |  |
The aggregate grant date fair value | $ 900,000 | $ 600,000 |
Aggregate intrinsic value | 1,000,000 | $ 800,000 |
Annual contribution for the purchase of shares | $ 5,000 |  |

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- Definition Aggregate proceeds received by the entity during the annual period from exercises of stock or unit options and conversion of similar instruments granted under equity-based payment arrangements. + 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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