Income Taxes - Jurisdictions the Company Remains Subject to Tax Examinations (Detail)	12 Months Ended
	Dec. 31, 2019
United States | Earliest Tax Year | Federal
Income Taxes [Line Items]
Tax Years	2016
United States | Earliest Tax Year | State
Income Taxes [Line Items]
Tax Years	2012
United States | Latest Tax Year | Federal
Income Taxes [Line Items]
Tax Years	2019
United States | Latest Tax Year | State
Income Taxes [Line Items]
Tax Years	2019
Ireland | Earliest Tax Year
Income Taxes [Line Items]
Tax Years	2015
Ireland | Latest Tax Year
Income Taxes [Line Items]
Tax Years	2019
United Kingdom | Earliest Tax Year
Income Taxes [Line Items]
Tax Years	2018
United Kingdom | Latest Tax Year
Income Taxes [Line Items]
Tax Years	2019