Income Taxes - Summary of Activity Related to Uncertain Tax Positions (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Summary of activity related to uncertain tax positions:
Beginning Balance	$ 2,269	$ 2,594	$ 3,561
Additions Based on Tax Positions Related to the Current Year	269	456	258
Additions for Tax Positions of Prior Years	615	232	293
Prior Year Reductions	(85)	(236)	(776)
Statute Expirations	(257)	(346)	(609)
Settlements	(282)	(431)	(133)
Ending Balance	$ 2,529	$ 2,269	$ 2,594

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

No definition available.

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- Definition

Amount of unrecognized tax benefits.

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Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities.

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Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.

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