Stock-Based Compensation - Summary of Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total pre-tax stock-based compensation expense charged against income	$ 1,838	$ 1,569
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total pre-tax stock-based compensation expense charged against income	664	771
Restricted stock and restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total pre-tax stock-based compensation expense charged against income	992	637
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total pre-tax stock-based compensation expense charged against income	$ 182	$ 161