Income Taxes - Net Deferred Income Tax Liabilities (Details 3) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Net deferred income tax liabilities
Deferred income tax assets	$ 77,201us-gaap_DeferredTaxAssetsGross	$ 68,829us-gaap_DeferredTaxAssetsGross
Deferred income tax liabilities	(55,045)us-gaap_DeferredTaxLiabilities	(48,830)us-gaap_DeferredTaxLiabilities
Valuation allowance	(20,507)	(17,741)
Net deferred income tax assets	$ 1,649us-gaap_DeferredTaxAssetsLiabilitiesNet	$ 2,258us-gaap_DeferredTaxAssetsLiabilitiesNet

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (b)

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-Publisher FASB

-Name Accounting Standards Codification

-Glossary Deferred Tax Asset

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Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards, net of deferred tax liability attributable to taxable temporary differences.

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Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

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Amount of deferred tax liability attributable to taxable temporary differences net of deferred tax asset attributable to deductible temporary differences and carryforwards after valuation allowances.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32537-109319

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-Name Accounting Standards Codification

-Topic 740

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-Section 45

-Paragraph 6

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