Income Taxes - Summary of Provision for Income Taxes and U.S. Federal Tax Rate (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Computed "expected" tax expense, amount	$ 187,601	$ 179,530	$ 141,249
Change in valuation allowance, amount	20,243	(53)	(222)
Foreign income tax differential, amount	(23,718)	(24,972)	(16,021)
State taxes net of federal benefits, amount	6,711	4,492	4,744
Foreign-sourced nontaxable income, amount	(10,573)	(8,128)	(11,967)
IRC Section 199 deduction, amount	(10,221)
Other, amount	3,530	(6,633)	1,285
Provision for income taxes, amount	$ 173,573	$ 144,236	$ 119,068
Computed "expected" tax expense, rate	35.00%	35.00%	35.00%
Change in valuation allowance, rate	3.80%
Foreign income tax differential, rate	(4.40%)	(4.90%)	(4.00%)
State taxes net of federal benefits, rate	1.20%	0.90%	1.20%
Foreign-sourced nontaxable income, rate	(2.00%)	(1.60%)	(3.00%)
IRC Section 199 deduction, rate	(1.90%)
Other, rate	0.70%	(1.30%)	0.30%
Provision for income taxes, rate	32.40%	28.10%	29.50%