Derivative Financial Instruments - Fair Values of Outstanding Zero Cost Collar Recorded as Assets and Liabilities (Detail) - Zero Cost Collars [Member] - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Asset Derivatives:
Derivatives designated as hedging instruments, Asset	$ 57
Liabilities Derivatives:
Derivatives designated as hedging instruments, Liability		$ 40
Other Current Liabilities [Member]
Liabilities Derivatives:
Derivatives designated as hedging instruments, Liability		$ 40
Other Current Assets [Member]
Asset Derivatives:
Derivatives designated as hedging instruments, Asset	$ 57