Share-Based Compensation - Schedule of Restricted Stock Units to be Settled in Cash (Detail) shares in Thousands	6 Months Ended
	Jun. 30, 2015 shares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Beginning balance of Outstanding, Stock Units to be Settled in Cash	1,842
Stock Units to be Settled in Cash, Granted	440
Stock Units to be Settled in Cash, Vested	(444)
Stock Units to be Settled in Cash, Forfeited	(386)
Ending balance of Outstanding, Stock Units to be Settled in Cash	1,452