Stock-Based Compensation - Stock Option Activity (Details) - Stock options - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Stock options, Shares Subject to Options
Outstanding at the beginning of the period (in shares)	1,988,696
Exercised (in shares)	(30,182)
Forfeited /Expired (in shares)	(3,113)
Outstanding at the end of the period (in shares)	1,955,401
Exercisable at the end of the period (in shares)	1,515,278
Exercisable and expected to vest at the end of the period (in shares)	1,919,442
Stock options, Weighted Average Option Price
Outstanding at the beginning of the period (in dollars per share)	$ 23.43
Exercised (in dollars per share)	23.07
Forfeited (in dollars per share)	22.84
Outstanding at the end of the period (in dollars per share)	23.39
Exercisable at the end of the period (in dollars per share)	20.89
Exercisable and expected to vest at the end of the period (in dollars per share)	$ 23.23
Stock options, additional information
Weighted Average Remaining Contractual Term, Outstanding	4 years 8 months 12 days
Weighted Average Remaining Contractual Term, Exercisable	4 years 6 months
Weighted Average Remaining Contractual Term, Exercisable and expected to vest	4 years 8 months 12 days
Aggregate Intrinsic Value, Outstanding	$ 25.4
Aggregate Intrinsic Value, Exercisable	22.7
Aggregate Intrinsic Value, Exercisable and expected to vest	$ 25.2
Fair value of the Company's common stock price (in dollars per share)	$ 35.86
Intrinsic value of options exercised	$ 300,000	$ 3,100,000