v3.4.0.3
Investments - Cost and Fair Value of Debt Investments Based on Maturities (Detail) - USD ($)
$ in Thousands
Mar. 31, 2016
Dec. 31, 2015
Available-for-sale Securities, Debt Maturities [Abstract]    
Due in one year or less, Amortized Costs $ 148,590 $ 152,444
Due within two years, Amortized Costs 135,104 130,110
Total, Amortized Costs 283,694 282,554
Due in one year or less, Fair Value 148,516 152,212
Due within two years, Fair Value 135,082 129,466
Total, Fair Value $ 283,598 $ 281,678