Computed Amount and Differences in Provision for Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Pretax income	$ 392,345	$ 392,440	$ 353,129
Computed amount at statutory rate of 35%	137,321	137,354	123,595
State and local income tax (net of federal tax benefit)	5,033	4,875	4,382
Taxes on non-U.S. earnings-net of foreign tax credits	(11,663)	(9,378)	(9,683)
Effect of flow-through entities	(8,358)	(9,018)	(7,267)
U.S. business tax credits	(1,273)	(1,680)	(1,516)
Domestic activities production deduction	(6,521)	(7,489)	(6,217)
Effective Income Tax Rate Reconciliation, Deferred tax effect of foreign tax rate change	(2,636)	0	0
Other	(2,365)	(1,610)	(5,380)
Total provision for income taxes	$ 109,538	$ 113,054	$ 97,914