Derivative Instruments - Gains (Losses) on Derivative Instruments and Classification on Consolidated Statement of Operations (Detail) - Designated As Hedging Instrument [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Gains recognized in OCI	$ 1,775	$ 834	$ 191
Losses recognized in OCI	(1,909)	(1,399)	(1,846)
Gains recognized from accumulated OCI into net loss	257	0	55
Losses recognized from accumulated OCI into net loss	$ (347)	$ (972)	$ (708)