Stockholders' Equity, Restricted Stock Unit Activity (Details) - Restricted Stock Units [Member] - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Number of Shares [Abstract]
Non-vested at beginning of period (in shares)	638
Granted (in shares)	348
Vested (in shares)	(196)
Cancelled/forfeited (in shares)	(39)
Non-vested at end of period (in shares)	751	638
Weighted Average Grant Date Fair Value per Share [Abstract]
Non-vested at beginning of period (in dollars per share)	$ 30.52
Granted (in dollars per share)	65.69	$ 44.94	$ 17.42
Vested (in dollars per share)	27.40
Cancelled/forfeited (in dollars per share)	42.87
Non-vested at end of period (in dollars per share)	$ 47.47	$ 30.52
Unrecognized Compensation Expense [Abstract]
Unrecognized compensation cost related to non-vested RSUs	$ 16.0
Weighted average period for recognition	1 year 2 months 12 days