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Share-Based Payments (Compensation Expense) (Details) - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2013
Summary of compensation expense and related tax benefit recognized during each period and compensation cost expense in future periods |  |  |
Share-based compensation expense | $ 9,166 | $ 10,056 | $ 9,242
Tax benefit recognized | 3,200 | 3,500 | 3,200
Unrecognized Compensation Cost, amount | 11,000 |  |
Restricted Stock Units (RSUs) [Member] |  |  |
Summary of compensation expense and related tax benefit recognized during each period and compensation cost expense in future periods |  |  |
Share-based compensation expense | 2,500 | 1,700 | 1,600
Unrecognized Compensation Cost, amount | $ 3,200 |  |
Unrecognized Compensation Cost, remaining recognition period | 1 year 9 months 18 days |  |
Performance Shares Units [Member] |  |  |
Summary of compensation expense and related tax benefit recognized during each period and compensation cost expense in future periods |  |  |
Share-based compensation expense | $ 5,900 | 7,600 | 7,100
Unrecognized Compensation Cost, amount | $ 6,000 |  |
Unrecognized Compensation Cost, remaining recognition period | 1 year 7 months 12 days |  |
Employee Purchase Plan [Member] |  |  |
Summary of compensation expense and related tax benefit recognized during each period and compensation cost expense in future periods |  |  |
Share-based compensation expense | $ 800 | $ 800 | $ 500
Unrecognized Compensation Cost, amount | $ 1,800 |  |
Unrecognized Compensation Cost, remaining recognition period | 2 years 2 months 12 days |  |

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- Definition Unrecognized cost of unvested share-based compensation awards. + 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 (i) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + 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 (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 The aggregate amount of noncash, equity-based employee remuneration. This may include the value of stock or unit options, amortization of restricted stock or units, and adjustment for officers' compensation. As noncash, this element is an add back when calculating net cash generated by operating activities using the indirect method. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3602-108585 + Details
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