Stock-Based Compensation - Changes in Nonvested Stock Options (Details)	12 Months Ended
	Dec. 31, 2017 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares [Roll Forward]
Options, Nonvested, Beginning balance (shares) | shares	225,175
Options, Nonvested, Granted (in shares) | shares	129,400
Options, Nonvested, Vested (shares) | shares	(90,625)
Options, Nonvested, Forfeited (shares) | shares	(44,150)
Options, Nonvested, Ending balance (shares) | shares	219,800
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Options, Nonvested, Weighted Average Grant Date Fair Value, Beginning balance, (in dollars per share) | $ / shares	$ 8.77
Options, Nonvested, Weighted Average Grant Date Fair Value, Granted, (in dollars per share) | $ / shares	11.88
Options, Nonvested, Weighted Average Grant Date Fair Value, Vested, (in dollars per share) | $ / shares	8.87
Options, Nonvested, Weighted Average Grant Date Fair Value, Forfeited, (in dollars per share) | $ / shares	7.93
Options, Nonvested, Weighted Average Grant Date Fair Value, Ending balance, (in dollars per share) | $ / shares	$ 11.07