Derivative Instruments and Hedging Activities - Schedule of Pre-tax Effect of Derivative Financial Instruments on Unaudited Condensed Consolidated Statements of Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Derivatives in Cash Flow Hedging Relationships:
Gain related to effective portion of derivatives recognized in accumulated other comprehensive loss	$ 12,116	$ 7,638
Loss related to effective portion of derivatives reclassified from accumulated other comprehensive loss to interest expense	$ (1,851)	$ (3,636)