Share-Based Compensation - Summary of Stock Option Activity (Details)	12 Months Ended
	Dec. 31, 2018 $ / shares shares
Shares
Outstanding, beginning of period (in shares) | shares	1,567,109
Granted (in shares) | shares	1,480,490
Exercised (in shares) | shares	(282,598)
Forfeited or Expired (in shares) | shares	(319,152)
Outstanding, end of period (in shares) | shares	2,445,849
Exercisable, end of period (in shares) | shares	515,977
Weighted Average Exercise Price
Outstanding, beginning of period (weighted average exercise price) | $ / shares	$ 25.27
Granted (weighted average exercise price) | $ / shares	34.49
Exercised (weighted average exercise price) | $ / shares	17.64
Forfeited or Expired (weighted average exercise price) | $ / shares	32.84
Outstanding, end of period (weighted average exercise price) | $ / shares	30.77
Exercisable, end of period (weighted average exercise price) | $ / shares	$ 21.89