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Stock-Based Compensation - Additional Information Pertaining to Option Activity (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Aggregate intrinsic value of stock options exercised $ 0.3 $ 0.1 $ 0.0
Cash received from the exercise of stock options 0.7 0.4 0.0
Tax benefit realized on exercise of stock options $ 0.1 $ 0.0 $ 0.0