Other Current Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Deposits in trusts for employee deferred compensation plans	$ 345,844	$ 311,708
Other	90,162	90,877
Other current assets	$ 436,006	$ 402,585