Debt Facilities - Interest Charges (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Debt Disclosure [Abstract]
Interest expense	$ 299,055	$ 270,553	$ 248,792
Interest capitalized	10,943	19,004	10,608
Interest charges incurred	$ 309,998	$ 289,557	$ 259,400