XML 40 R30.htm IDEA: XBRL DOCUMENT v3.7.0.1
Summary of Gross Realized Gains and Losses from Sale of Available-for-Sale Marketable Securities (Detail) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Jun. 30, 2017
Jun. 30, 2016
Investments, Debt and Equity Securities [Abstract]        
Gross realized gains from sale of available-for-sale marketable securities $ 6 $ 15 $ 6 $ 15
Gross realized losses from sale of available-for-sale marketable securities $ (8) $ (1) $ (46) $ (31)