Investments - Additional Information (Detail) $ in Thousands |
Mar. 31, 2016
USD ($)
Securities
|
Dec. 31, 2015
USD ($)
Securities
|
---|---|---|
Investments, Debt and Equity Securities [Abstract] | ||
Number of debt securities with unrealized loss position for less than one year | 14 | 69 |
Aggregate fair value of debt securities | $ | $ 26,457 | $ 117,851 |
Number of debt securities with unrealized loss position for greater than one year | 0 | 0 |