Stock Option and Compensation Plans - Summary of Stock Option Activity (Details) shares in Thousands	9 Months Ended
	Sep. 30, 2016 $ / shares shares
Common Stock Options
Outstanding, December 31, 2015 (in shares) | shares	3,009
Granted (in shares) | shares	952
Exercised (in shares) | shares	(350)
Expired or forfeited (in shares) | shares	(188)
Outstanding, September 30, 2016 (in shares) | shares	3,423
Weighted Average Exercise Price
Outstanding, December 31, 2015 (in dollars per share) | $ / shares	$ 30.43
Granted (in dollars per share) | $ / shares	60.81
Exercised (in dollars per share) | $ / shares	16.89
Expired or forfeited (in dollars per share) | $ / shares	48.59
Outstanding, September 30, 2016 (in dollars per share) | $ / shares	$ 39.26
Options exercisable at September 30, 2016 (in shares) | shares	1,399
Weighted average grant date fair value (per share) of options granted during the period (in dollars per share) | $ / shares	$ 38.49