Income Taxes - Gross Unrecognized Tax Benefits Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of the beginning and ending amount of gross unrecognized tax benefits
Balance as of beginning of period	$ 12,597	$ 13,528	$ 30,176
Additions for current year tax positions	3,274	3,371	2,734
Additions for tax positions of prior years	141	949	118
Reductions for tax positions of prior years	(173)	(1,807)	(35)
Reductions due to lapses of applicable statutes of limitations	(2,235)	(3,071)	(19,465)
Reductions due to settlements with taxing authorities		(373)
Balance as of end of period	13,604	12,597	$ 13,528
Unrecognized tax benefits realized that would have reduced income tax expense	$ 9,100	$ 8,600

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15A
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=65882285&loc=SL6600010-109319

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Unrecognized Tax Benefit
-URI http://asc.fasb.org/extlink&oid=6527854

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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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Amount of increase 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 lapses of applicable statutes of limitations.

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The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate.

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