Other Comprehensive Loss - Changes in Accumulated Other Comprehensive Loss by Component (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	$ 2,897,438
Total other comprehensive (loss) income	(279)	$ 805
Ending Balance	2,772,323
Gains and Losses on Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(2,100)
Other comprehensive income (loss) before reclassifications	3
Change in cash flow hedges reclassed to earnings	117
Total other comprehensive (loss) income	120
Ending Balance	(1,980)
Foreign Currency Items [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	994
Other comprehensive income (loss) before reclassifications	(325)
Change in cash flow hedges reclassed to earnings	0
Total other comprehensive (loss) income	(325)
Ending Balance	669
Total [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(1,106)
Other comprehensive income (loss) before reclassifications	(322)
Change in cash flow hedges reclassed to earnings	117
Total other comprehensive (loss) income	(205)
Ending Balance	$ (1,311)