Shareholders' Equity - Additional Information (Detail) - USD ($)		3 Months Ended		9 Months Ended		12 Months Ended
	Dec. 06, 2016	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2014	Sep. 19, 2017	Dec. 31, 2016
Stockholders Equity Note Disclosure [Line Items]
Common Stock, Shares Authorized		426,000,000.0		426,000,000.0				426,000,000
Common Stock, Par or Stated Value Per Share		$ 0.01		$ 0.01				$ 0.01
Dividends Payable, Amount Per Share							$ 0.345
Cash dividends paid per ordinary share		$ 0.345	$ 0.34	$ 1.035	$ 1.00
Share repurchase (in shares)				1,500,000
Stock Repurchased During Period, Value				$ 100,000,000
ApprovedNotDeclaredlDividends	$ 1.38
Dividends payable		$ 62,700,000		62,700,000				$ 61,800,000
December 2014 Share Repurchase Program [Member]
Stockholders Equity Note Disclosure [Line Items]
Repurchase of shares of our common stock up to a maximum aggregate value						$ 1,000,000,000.0
Common stock authorized for repurchase, expiration date						Dec. 31, 2019
Share repurchase program remaining available amount		$ 700,000,054		$ 700,000,054