Investments and Fair Value Measurements - Schedule of Maturity Profile of Held-to-maturity Investments (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Investments, Debt and Equity Securities [Abstract]
Held-to-maturity due within one year
Held-to-maturity due one year through five years
Held-to-maturity due five years through ten years	665	686
Held-to-maturity due over ten years	11,559	11,062
Held-to-maturity total	$ 12,224	$ 11,748