XML 43 R32.htm IDEA: XBRL DOCUMENT v3.8.0.1
Revolving Line of Credit - Additional Information (Detail)
3 Months Ended
Mar. 31, 2018
USD ($)
Debt Instrument [Line Items]  
Credit facility, borrowing outstanding $ 0
Revolving Credit Facility  
Debt Instrument [Line Items]  
Line of credit, current borrowing capacity $ 150,000,000
Line of credit, expiration date Mar. 31, 2023