Short-Term and Long-Term Investments - Amortized Cost and Estimated Fair Value of Available-for-Sale Securities by Contractual Maturities (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Available For Sale Securities Debt Maturities [Abstract]
Due in one year or less, Cost	$ 640
Due in two to ten years, Cost	90
Due in twenty to forty years, Cost	6,000
Total Cost	6,730	6,820
Due in one year or less, Estimated Fair Value	642
Due in two to ten years, Estimated Fair Value	91
Due in twenty to forty years, Estimated Fair Value	4,904
Estimated Fair Value	$ 5,637	$ 5,651