Acquisitions and Divestitures - Unaudited Pro Forma Operating Results (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Combinations [Abstract]
Net Sales	$ 698,437	$ 654,877	$ 651,252
Net Income	$ 49,317	$ 43,559	$ 47,956
Earnings Per Share [Abstract]
Basic (in dollars per share)	$ 2.89	$ 2.58	$ 2.86
Diluted (in dollars per share)	$ 2.85	$ 2.53	$ 2.81