Basis of Financial Statement Presentation - Narrative (Details) - USD ($) $ in Thousands		3 Months Ended
	Jan. 01, 2018	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
New Accounting Pronouncement, Early Adoption [Line Items]
Effect on revenue		$ 191,660
Effect on net sales		191,660	$ 165,487
Effect on net income		11,054	11,669
Effect on retained earnings	$ 376,381	387,435		$ 374,783
Cost of sales		152,153	124,989
Selling, product development and administrative expenses		25,471	$ 25,350
Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
New Accounting Pronouncement, Early Adoption [Line Items]
Effect on revenue	19,600
Effect on net sales	16,300	6,254
Effect on net income		236
Effect on retained earnings	$ 1,598	1,834
Cost of sales		5,962
Selling, product development and administrative expenses		0
Accounting Standards Update 2017-07
New Accounting Pronouncement, Early Adoption [Line Items]
Cost of sales		100
Selling, product development and administrative expenses		$ 100