XML 75 R64.htm IDEA: XBRL DOCUMENT v3.8.0.1
Commitments and Contingencies - Additional Information (Detail) - USD ($)
3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Dec. 31, 2017
Other Commitments [Line Items]      
Outstanding letter of credit, amount $ 1,100,000    
Amounts drawn against outstanding letters of credit or performance bond 0 $ 0  
Restricted Escrow Deposits 1,000,000   $ 1,000,000
Performance Bonds [Member]      
Other Commitments [Line Items]      
Outstanding performance and payment of bonds $ 4,500,000 $ 4,200,000