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Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Income Tax Contingency [Line Items]
Gross liability for unrecognized tax benefits, exclusive of interest and penalties	$ 14,342	$ 14,480
Unrecognized tax benefits that would affect effective tax rate	13,670	13,737
Interest and penalties on unrecognized benefits	1,366	$ 1,175
Estimated one-time transition tax	10,711
Payment of transition tax	1,000
Overpayment of federal taxes	8,941
Transition tax, noncurrent	770
Settlement and Lapse of Statute
Income Tax Contingency [Line Items]
Unrecognized tax benefits within the next twelve months	$ 1,398

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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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15
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