Shareholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, shares in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Oct. 01, 2017	Sep. 30, 2018	Oct. 01, 2017	Dec. 31, 2018	Aug. 31, 2018	May 31, 2018	Jan. 31, 2018	Aug. 31, 2017	May 31, 2017	Jan. 31, 2017	Dec. 31, 2016
Stockholders Equity Note Disclosure [Line Items]
Stock repurchase program, authorized amount												$ 500,000,000
Cumulative repurchases, value			$ 562,300	$ 151,800,000
Cumulative repurchases, shares			13.8	4.6
Common stock average price			$ 40.62	$ 32.66
Dividends payable, amount per share						$ 0.09	$ 0.09	$ 0.09	$ 0.07	$ 0.07	$ 0.07
Dividend payment	$ 16,600,000	$ 13,800,000	$ 51,320,000	$ 41,730,000
Scenario, Forecast
Stockholders Equity Note Disclosure [Line Items]
Cumulative repurchases, value					$ 750,000,000
Maximum
Stockholders Equity Note Disclosure [Line Items]
Stock repurchase program, authorized amount								$ 1,500,000,000