Income Taxes - Reconciliation of beginning and ending amount of unrecognized tax benefits (Details 3) - USD ($)	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014
Reconciliation of Unrecognized Tax Benefits [Roll Forward]
Balance at January 1	$ 23,267,000	$ 16,345,000
Additions based on tax positions related to the current year	2,171,000	5,193,000
Additions for tax positions of prior years	714,000	1,729,000
Balance at December 31	$ 26,152,000	$ 23,267,000

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 pertaining to uncertain tax positions taken in tax returns.

+ 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=6907707&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

+ Details

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- Definition

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

+ References

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- Definition

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

+ References

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