Income Taxes - Income Tax Temporary Differences Table (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Depreciable property	$ (10,057)	$ (7,676)
Credit carryforwards	497	448
Other intangible assets	(299)	(189)
Other	162	8
Net long-term deferred income tax liabilities	$ (9,697)	$ (7,409)

Amount, after deferred tax asset, of deferred tax liability attributable to taxable differences with jurisdictional netting.

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Amount, before allocation of valuation allowance, of deferred tax asset attributable to deductible temporary differences, classified as other.

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Amount of deferred tax liability attributable to taxable temporary differences from intangible assets other than goodwill.

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