Income Taxes - A Reconciliation of the Beginning and Ending Balances of our Liability for Unrecognized Tax Benefits (Details 5) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Unrecognized tax benefits
Balance, beginning of year	$ 9,517us-gaap_UnrecognizedTaxBenefits	$ 4,029us-gaap_UnrecognizedTaxBenefits	$ 4,114us-gaap_UnrecognizedTaxBenefits
Additions based on tax positions related to current year	760	1,292	276
Additions for tax positions of prior years	30	4,597	933
Reductions for tax positions of prior years	(677)	(401)	(764)
Lapse of statute of limitations			(530)
Balance, end of year	$ 9,630us-gaap_UnrecognizedTaxBenefits	$ 9,517us-gaap_UnrecognizedTaxBenefits	$ 4,029us-gaap_UnrecognizedTaxBenefits

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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

-Glossary Unrecognized Tax Benefit

-URI http://asc.fasb.org/extlink&oid=6527854

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-Publisher FASB

-Name Accounting Standards Codification

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-Section 50

-Paragraph 15A

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

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-URI http://asc.fasb.org/extlink&oid=6907707&loc=SL6600010-109319

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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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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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-Name Accounting Standards Codification

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