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Stock-Based Compensation - Summary of Stock Option Activity (Details)
9 Months Ended
Sep. 30, 2018
$ / shares
shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]  
Number of Shares, Beginning Balance (in shares) | shares 109,808
Number of Shares, Exercised (in shares) | shares (23,675)
Number of Shares, Ending Balance (in shares) | shares 86,133
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]  
Weighted Average Exercise Price, Beginning Balance (in $ per share) | $ / shares $ 16.44
Weighted Average Exercise Price, Exercised (in $ per share) | $ / shares 30.38
Weighted Average Exercise Price, Ending Balance (in $ per share) | $ / shares $ 12.61