Stock-Based Compensation (Stock Option Activity) (Details) - Stock Options shares in Thousands	3 Months Ended
	Mar. 31, 2017 $ / shares shares
Number of Shares
Options outstanding at the beginning of the period (in shares) | shares	3,606
Options granted (in shares) | shares	624
Options exercised (in shares) | shares	(290)
Options forfeited (in shares) | shares	(15)
Options expired (in shares) | shares	(3)
Options outstanding at the end of the period (in shares) | shares	3,922
Exercisable at the end of the period (in shares) | shares	2,540
Vested and expected to vest at the end of the period (in shares) | shares	3,803
Weighted-Average Exercise Price
Options outstanding at the beginning of the period (in dollars per share) | $ / shares	$ 25.07
Options granted (in dollars per share) | $ / shares	27.48
Options exercised (in dollars per share) | $ / shares	20.91
Options forfeited (in dollars per share) | $ / shares	28.67
Options expired (in dollars per share) | $ / shares	20.48
Options outstanding at the end of the period (in dollars per share) | $ / shares	25.75
Exercisable at the end of the period (in dollars per share) | $ / shares	24.58
Vested and expected to vest at the end of the period (in dollars per share) | $ / shares	$ 25.69