Income Taxes - Schedule of Provision (Benefit) for Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Federal, current	$ 349	$ 1,766	$ 8,177
Foreign, current	64,119	54,253	78,086
State and local (primarily UBT), current	(32)	4,090	4,970
Total current	64,436	60,109	91,233
Federal, deferred	480,085	50,602	(988,900)
Foreign, deferred	12,928	1,354	(3,960)
State and local, deferred	8,150	11,704	(107,925)
Total deferred	501,163	63,660	(1,100,785)
Total	$ 565,599	$ 123,769	$ (1,009,552)