Derivative Instruments - Gains (Losses) on Derivative Instruments and Classification on Condensed Consolidated Statement of Operations (Detail) - Designated As Hedging Instrument [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Derivatives, Fair Value [Line Items]
Gains recognized in OCI	$ 2,887	$ 1,316
Losses recognized in OCI	0	(99)
Gains recognized from accumulated OCI into net income	206	0
Losses recognized from accumulated OCI into net income	$ (5)	$ (194)