Income Taxes - Reconciliation of Tax Provision for Continuing Operations (Detail)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2017 Rate	Dec. 31, 2016	Dec. 31, 2016 Rate	Dec. 31, 2015	Dec. 31, 2015 Rate
Income Tax Disclosure [Abstract]
Tax provision at U.S. statutory rate		35.00%		35.00%		35.00%
Federal deferred taxes remeasurement - Tax Act		27.80%		0.00%		0.00%
One-time tax on foreign earnings - Tax Act		18.80%		0.00%		0.00%
Foreign tax rate differential		(8.60%)		(3.50%)		(4.70%)
Tax exempt interest		(7.80%)		(5.20%)		(6.70%)
Valuation allowance on deferred tax assets		7.20%		1.40%		3.30%
Tax on undistributed foreign earnings		(4.80%)		4.90%		(5.60%)
U.S. permanent items		(2.20%)		(1.90%)		(1.00%)
Italy patent box prior year benefit		(1.10%)		0.00%		0.00%
Audit settlements and unrecognized tax benefits		(0.80%)		(5.20%)		(5.00%)
U.S. tax on foreign earnings		0.30%		4.70%		3.80%
State and local income tax		0.30%		(0.10%)		1.00%
Foreign tax holiday		0.00%		0.00%		(1.10%)
Other adjustments		(1.20%)		(0.70%)		(0.70%)
Effective income tax rate	62.90%	62.90%	29.40%	29.40%	18.30%	18.30%