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Retirement Plans Employee Retirement Plan (Details) (USD $)
In Thousands, unless otherwise specified |
12 Months Ended | ||
|---|---|---|---|
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Dec. 31, 2012
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Dec. 31, 2011
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Dec. 31, 2010
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| Defined Benefit Plan Disclosure [Line Items] | |||
| Defined Contribution Plan, Maximum Annual Contribution Per Employee, Percent | 4.00% | ||
| Defined Contribution Plan, Employer Matching Contribution, Percent | 50% of the first 4% | ||
| Defined Contribution Plan, Cost Recognized | $ 1,070 | $ 930 | $ 803 |