XML 44 R32.htm IDEA: XBRL DOCUMENT v3.19.2
Financial Instruments - Additional Information (Detail)
6 Months Ended
Jun. 30, 2019
USD ($)
Financial Instrument [Line Items]  
Material realized gains or losses on available-for-sale securities $ 0
Maximum  
Financial Instrument [Line Items]  
Available for sale debt securities contractual maturities 1 year