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Income Taxes (Narrative) (Details) - USD ($) $ in Thousands | Mar. 31, 2018 | Dec. 31, 2017
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Income Tax Contingency [Line Items] |  |
Gross liability for unrecognized tax benefits, exclusive of interest and penalties | $ 14,685 | $ 14,480
Unrecognized tax benefits that would affect effective tax rate | 13,986 | 13,737
Interest and penalties on unrecognized benefits | 1,218 | $ 1,175
Estimated one-time transition tax | 11,544 |
Estimated one-time transition tax, current | 915 |
Estimated one-time transition tax, noncurrent | 10,629 |
Settlement and Lapse of Statute [Member] |  |
Income Tax Contingency [Line Items] |  |
Unrecognized tax benefits within the next twelve months | $ 2,944 |

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- Definition The amount of the unrecognized tax benefit of a position taken for which it is reasonably possible that the total amount thereof will significantly increase or decrease within twelve months of the balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32718-109319 + Details
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- Definition Amount accrued for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32718-109319 + Details
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