Subsequent Events - Additional Information (Detail) - Subsequent Event $ in Millions	1 Months Ended
May. 16, 2016 USD ($)
Subsequent Event [Line Items]
Cash	$ 4.9
Restricted Stock Units (RSUs)
Subsequent Event [Line Items]
Share awards	11.0
Stock options
Subsequent Event [Line Items]
Share awards	$ 1.0

Amount of expense recognized from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments), awarded to key employees or individuals. Excludes amount related to plans that cover generally all employees (for example, but not limited to, qualified pension plans).

No definition available.

Name:	us-gaap_DeferredCompensationArrangementWithIndividualAllocatedShareBasedCompensationExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration