Stock-based Compensation - Employee Stock Purchase Plan (Details) - Employee stock purchase plan	12 Months Ended
	Dec. 31, 2015 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options outstanding, Beginning balance (in shares) | shares	374,703
Granted (in shares) | shares	1,530,127
Exercised (in shares) | shares	(1,532,264)
Options outstanding, Ending balance (in shares) | shares	372,566
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted-average exercise price, Outstanding, Beginning of period (in dollars per share) | $ / shares	$ 45.46
Weighted-average exercise price, Granted (in dollars per share) | $ / shares	44.75
Weighted-average exercise price, Exercised (in dollars per share) | $ / shares	44.57
Weighted-average exercise price, Outstanding, End of period (in dollars per share) | $ / shares	$ 46.19