Recent Accounting Standards (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 29, 2018	Jan. 01, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings	$ 596,270	$ 578,293	$ 587,877
Accounting Standard Update 2017-07 | Operating income
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Effect of adoption	4,900
Accounting Standard Update 2017-07 | Other nonoperating income
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Effect of adoption	12,700
Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings	$ (127)	$ (9,584)