Stock-based Compensation - Weighted Average Valuation Assumptions (Details) - Stock options - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend Yield	0.30%	0.40%	0.40%
Expected Volatility	34.80%	32.80%	34.20%
Risk-free Interest Rate	2.60%	1.90%	1.30%
Expected Term (in years)	5 years 3 months 12 days	5 years 3 months 12 days	5 years 3 months 12 days
Weighted-average Fair Value of Stock Options Granted (in dollars per share)	$ 16.54	$ 8.55	$ 7.10