Quarterly report pursuant to Section 13 or 15(d)

Revenue from Contracts with Customers - Additional Information (Detail)

v3.10.0.1
Revenue from Contracts with Customers - Additional Information (Detail) - Contract
3 Months Ended 6 Months Ended
Jun. 30, 2018
Jun. 30, 2017
Jun. 30, 2018
Jun. 30, 2017
Disaggregation of Revenue [Line Items]        
Contract periods     One year or less  
Number of contracts     0  
Non-US [Member] | Geographic Concentration Risk [Member] | Revenue | Maximum        
Disaggregation of Revenue [Line Items]        
Revenue earned, percent 1.00% 1.00% 1.00% 1.00%