Investments and Fair Value Measurements - Schedule of Maturity Profile of Investments (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Held-to-maturity due within one year	$ 0	$ 0
Held-to-maturity due one year through five years	8,369	1,409
Held-to-maturity due five years through ten years	3,127	350
Held-to-maturity due over ten years	12,193	12,231
Held-to-maturity cost or amortized cost	$ 23,689	$ 13,990