Stock-Based Compensation - Stock Options Activity (Details)	12 Months Ended
	Dec. 31, 2017 $ / shares shares
Number of Shares
Outstanding at beginning of period (in shares) | shares	173,757
Granted (in shares) | shares	26,112
Forfeited (in shares) | shares	(4,525)
Exercised (in shares) | shares	(51,899)
Outstanding at end of period (in shares) | shares	143,445
Weighted Average Exercise Price
Outstanding at beginning of period (in USD per share) | $ / shares	$ 23.65
Granted (in USD per share) | $ / shares	33.03
Forfeited (in USD per share) | $ / shares	23.00
Exercised (in USD per share) | $ / shares	19.72
Outstanding at end of period (in USD per share) | $ / shares	$ 26.79
Weighted average remaining contractual life, Outstanding at end of period	5 years 219 days