New Accounting Pronouncements - Schedule of New Accounting Standards Adoption Impacts Statement of Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jul. 01, 2017	Jun. 30, 2018	Jul. 01, 2017
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Net Revenue	$ 88,604	$ 64,427	$ 170,917	$ 123,741
Net income	$ 17,675	$ 8,288	$ 34,056	$ 13,640
Net income per share:
Basic (in dollars per share)	$ 0.74	$ 0.33	$ 1.42	$ 0.54
Diluted (in dollars per share)	$ 0.72	$ 0.32	$ 1.39	$ 0.53
Topic 606 Adoption [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Net Revenue	$ 3,300
Calculated under Revenue Guidance in Effect before Topic 606 | Topic 606 Adoption [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Net Revenue	89,153		$ 167,190
Net income	$ 18,291		$ 31,611
Net income per share:
Basic (in dollars per share)	$ 0.76		$ 1.32
Diluted (in dollars per share)	$ 0.75		$ 1.29
Effect of Change Higher/(Lower) [Member] | Topic 606 Adoption [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Net Revenue	$ (549)		$ 3,727
Net income	$ (616)		$ 2,445
Net income per share:
Basic (in dollars per share)	$ (0.03)		$ 0.10
Diluted (in dollars per share)	$ (0.03)		$ 0.10