Stock-based Compensation - Schedule of Non-Vested RSUs (Detail) - RSUs [Member] shares in Thousands	9 Months Ended
	Sep. 30, 2015 $ / shares shares
Nonvested Restricted Stock Units Activity [Line Items]
Non-vested, beginning balance	2,003
Shares, Restricted stock granted	1,034
Shares, Restricted stock vested	(857)
Shares, Restricted stock forfeited	(357)
Non-vested, ending balance	1,823
Weighted average grant date fair value, Non-vested, beginning balance | $ / shares	$ 35.91
Weighted average grant date fair value, Restricted stock granted | $ / shares	41.29
Weighted average grant date fair value, Restricted stock vested | $ / shares	(32.03)
Weighted average grant date fair value, Restricted stock forfeited | $ / shares	(39.10)
Weighted average grant date fair value, Non-vested, ending balance | $ / shares	$ 39.73