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Goodwill and Intangible Assets - Additional Information (Detail) - USD ($)
$ in Thousands
 3 Months Ended 12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Jun. 30, 2014
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Oct. 01, 2014
Intangible Assets [Line Items]              
Total amortization expense on intangible assets       $ 4,600 $ 3,600 $ 3,800  
Impairment of intangible assets     $ 5,600        
Goodwill $ 0 $ 52,012   $ 0 $ 52,012    
Goodwill impairment loss 5,500            
Contractual Rights [Member]              
Intangible Assets [Line Items]              
Remaining amortization period for intangibles (in years)       14 years      
Other Intangible Assets [Member]              
Intangible Assets [Line Items]              
Remaining amortization period for intangibles (in years)       31 years      
VantaCore Partners LP              
Intangible Assets [Line Items]              
Acquisition of goodwill   $ 52,000          
Increase (decrease) in goodwill       $ (46,500)      
Goodwill             $ 5,525
Goodwill impairment loss $ 5,500