Stock-Based Compensation (Stock Option Activity) (Details) shares in Thousands	3 Months Ended
	Mar. 31, 2016 $ / shares shares
Number of Shares
Options outstanding at the beginning of the period (in shares) | shares	3,630
Options granted (in shares) | shares	583
Options exercised (in shares) | shares	(36)
Options forfeited (in shares) | shares	(11)
Options expired (in shares) | shares	(3)
Options outstanding at the end of the period (in shares) | shares	4,163
Exercisable at the end of the period (in shares) | shares	3,023
Vested and expected to vest at the end of the period (in shares) | shares	4,033
Weighted-Average Exercise Price
Options outstanding at the beginning of the period (in dollars per share) | $ / shares	$ 23.80
Options granted (in dollars per share) | $ / shares	27.00
Options exercised (in dollars per share) | $ / shares	17.72
Options forfeited (in dollars per share) | $ / shares	29.94
Options expired (in dollars per share) | $ / shares	20.64
Options outstanding at the end of the period (in dollars per share) | $ / shares	24.29
Exercisable at the end of the period (in dollars per share) | $ / shares	22.66
Vested and expected to vest at the end of the period (in dollars per share) | $ / shares	$ 24.16