Quarterly report pursuant to Section 13 or 15(d)

Intangible Assets, Net - Summary of Intangible Assets (Detail)

v3.19.2
Intangible Assets, Net - Summary of Intangible Assets (Detail) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended 12 Months Ended
Jun. 30, 2019
Jun. 30, 2018
Jun. 30, 2019
Jun. 30, 2018
Dec. 31, 2018
Dec. 31, 2017
Cost of intangible assets gross $ 25,027   $ 25,027   $ 25,027 $ 25,027
Accumulated amortization, beginning balance     (15,134) $ (13,449) (13,449)  
Amortization expense (347) $ (420) (695) (845) (1,685)  
Accumulated amortization, ending balance (15,829)   (15,829)   (15,134)  
Net book value 9,198   $ 9,198   9,893  
Minimum            
Useful lives     3 years      
Maximum            
Useful lives     20 years      
Customer Relationships            
Cost of intangible assets gross 22,560   $ 22,560   22,560 22,560
Accumulated amortization, beginning balance     (12,887) (11,367) (11,367)  
Amortization expense     (615)   (1,520)  
Accumulated amortization, ending balance (13,502)   (13,502)   (12,887)  
Net book value 9,058   $ 9,058   $ 9,673  
Customer Relationships | Minimum            
Useful lives     10 years   10 years  
Customer Relationships | Maximum            
Useful lives     20 years   20 years  
Other Intangible Assets            
Cost of intangible assets gross 2,467   $ 2,467   $ 2,467 $ 2,467
Accumulated amortization, beginning balance     (2,247) $ (2,082) (2,082)  
Amortization expense     (80)   (165)  
Accumulated amortization, ending balance (2,327)   (2,327)   (2,247)  
Net book value $ 140   $ 140   $ 220  
Other Intangible Assets | Minimum            
Useful lives     3 years   3 years  
Other Intangible Assets | Maximum            
Useful lives     5 years   5 years