Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 01, 2017	Oct. 02, 2016	Oct. 01, 2017	Oct. 02, 2016
Income Tax Disclosure [Abstract]
Effective tax rate	21.70%	30.20%	26.70%	33.80%
Provision for income taxes	$ 5,767	$ 9,144	$ 18,678	$ 27,464
Possible reduction in liabilities for uncertain tax positions	900		900
Adjustments from Change in Estimates [Member]
Income tax expense (benefit) [Line Items]
Other income tax benefit (expense)		$ 1,800		$ 1,800
Adjustments for New Accounting Pronouncement [Member] | ASU 2016-09 [Member]
Income tax expense (benefit) [Line Items]
Other income tax benefit (expense)	300		2,100
Adjustments from Completion of Tax Audits [Member]
Income tax expense (benefit) [Line Items]
Other income tax benefit (expense)	$ 2,100		$ 2,100