Information with Respect to Ordinary Shares that were Surrendered, Repurchased or Redeemed (Detail) - Ordinary Shares A - USD ($)		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015
Equity, Class of Treasury Stock [Line Items]
Total Number of Shares Purchased or Redeemed		28,099	8,272,765
Average Price Paid Per Share		$ 28.64	$ 23.01
Total Number of Shares Purchased as Part of Publicly Announced Plan or Program		0	0
Approximate Dollar Value of Shares that May Yet Be Purchased Under the Plans or Programs		$ 0	$ 0
January 1-31, 2016
Equity, Class of Treasury Stock [Line Items]
Total Number of Shares Purchased or Redeemed	[1],[2]	12,410
Average Price Paid Per Share	[1]	$ 29.02
Total Number of Shares Purchased as Part of Publicly Announced Plan or Program		0
Approximate Dollar Value of Shares that May Yet Be Purchased Under the Plans or Programs		$ 0
February 1 - 29, 2016
Equity, Class of Treasury Stock [Line Items]
Total Number of Shares Purchased or Redeemed	[1],[2]	15,093
Average Price Paid Per Share	[1]	$ 28.25
Total Number of Shares Purchased as Part of Publicly Announced Plan or Program		0
Approximate Dollar Value of Shares that May Yet Be Purchased Under the Plans or Programs		$ 0
May 1 - 31, 2016
Equity, Class of Treasury Stock [Line Items]
Total Number of Shares Purchased or Redeemed	[1],[2]	596
Average Price Paid Per Share	[1]	$ 30.56
Total Number of Shares Purchased as Part of Publicly Announced Plan or Program		0
Approximate Dollar Value of Shares that May Yet Be Purchased Under the Plans or Programs		$ 0
January 1-31, 2015
Equity, Class of Treasury Stock [Line Items]
Total Number of Shares Purchased or Redeemed	[1],[2]		9,009
Average Price Paid Per Share	[1]		$ 28.37
Total Number of Shares Purchased as Part of Publicly Announced Plan or Program			0
Approximate Dollar Value of Shares that May Yet Be Purchased Under the Plans or Programs			$ 0
March 1-31, 2015
Equity, Class of Treasury Stock [Line Items]
Total Number of Shares Purchased or Redeemed	[1],[2]		2,290
Average Price Paid Per Share	[1]		$ 26.98
Total Number of Shares Purchased as Part of Publicly Announced Plan or Program			0
Approximate Dollar Value of Shares that May Yet Be Purchased Under the Plans or Programs			$ 0
May 1-31, 2015
Equity, Class of Treasury Stock [Line Items]
Total Number of Shares Purchased or Redeemed	[1],[2]		596
Average Price Paid Per Share	[1]		$ 27.01
Total Number of Shares Purchased as Part of Publicly Announced Plan or Program			0
Approximate Dollar Value of Shares that May Yet Be Purchased Under the Plans or Programs			$ 0
November 1-30, 2015
Equity, Class of Treasury Stock [Line Items]
Total Number of Shares Purchased or Redeemed	[1],[3]		8,260,870
Average Price Paid Per Share	[1]		$ 23.00
Total Number of Shares Purchased as Part of Publicly Announced Plan or Program			0
Approximate Dollar Value of Shares that May Yet Be Purchased Under the Plans or Programs			$ 0

[1] Based on settlement date.

[2] Surrendered by employees as payment of taxes withheld on the vesting of restricted stock.

[3] Of these shares, 7,928,004 shares were converted from B ordinary shares to A ordinary shares. Of the 7,928,004 converted shares, 4,555,061 were redeemed and 3,372,943 went into a liquidating trust.