Income Taxes - Reconciliation of Effective Tax Rate on Income or Loss and Statutory Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Statutory U.S. tax rate	35.00%	35.00%	35.00%
State income taxes, net of U.S. tax benefit	3.50%	1.90%	0.90%
Federal and State tax credits, net of U.S. tax benefit	(11.50%)	(9.80%)	22.60%
Foreign income taxed at other than U.S. statutory rate	(2.40%)	(13.40%)	(5.10%)
Effective Income Tax Rate Reconciliation, Effect of Foreign Tax Rate Changes	0.90%	1.30%	(4.20%)
Foreign tax credit	(12.00%)	(13.50%)	9.40%
Basis differences of intangibles with an indefinite life	0.10%	0.10%	(4.10%)
Change in deferred tax valuation allowance	0.30%	35.30%	(76.80%)
Accrual for interest and income taxes related to uncertain tax positions	(0.30%)	(7.30%)	(0.10%)
Income (loss) from flowthrough entities	(2.00%)	(1.90%)	1.30%
Meals and entertainment	3.40%	3.30%	(7.20%)
Group loss relief	(3.70%)	(2.60%)	4.90%
Stock option compensation	(1.90%)	2.30%	(6.90%)
Foreign dividends and earnings inclusion	7.10%	(0.90%)	(6.80%)
Foreign tax withholding	1.40%	2.40%	(1.50%)
Executive compensation limitation	4.30%	0.00%	0.00%
Other	5.20%	(6.20%)	(3.40%)
Effective tax rate	27.40%	26.00%	(42.00%)