Income Taxes - Summary of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands  | 
Dec. 31, 2016  | 
Dec. 31, 2015  | 
|---|---|---|
| Deferred tax assets | ||
| Intangible assets | $ 21,792 | $ 22,880 | 
| Other | 12 | |
| Total deferred tax assets | 21,792 | 22,892 | 
| Deferred tax liabilities | ||
| Intangible assets | 221 | 241 | 
| Investment on underlying SLP partnership | 1,571 | 1,382 | 
| Other | 11 | |
| Total deferred tax liabilities | 1,803 | 1,623 | 
| Net deferred tax assets (liabilities) | $ 19,989 | $ 21,269 | 
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- Definition Deferred income tax liabilities investment on underlying SLP partnership. No definition available. 
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- Definition Amount of deferred tax liability attributable to taxable temporary differences. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from intangible assets including goodwill. No definition available. 
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- Definition Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- References No definition available. 
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- Definition Amount, after allocation of valuation allowances and deferred tax liability, of deferred tax asset attributable to deductible differences and carryforwards, without jurisdictional netting. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Amount, before allocation of valuation allowance, of deferred tax asset attributable to deductible temporary differences, classified as other. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- References No definition available. 
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- Definition Amount of deferred tax liability attributable to taxable temporary differences from intangible assets other than goodwill. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Amount of deferred tax liability attributable to taxable temporary differences classified as other. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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