Nature of Operations and Summary of Significant Accounting Policies - Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017
Accounting Policies [Abstract]
Cash Paid for Interest	$ 5,914	$ 1,421
Cash Paid for Income Taxes, Net of Refunds	20,823	12,479
Non-Cash Investing Activities:
Estimated post-closing adjustment	397	0
Fair value of assets acquired	0	241,141
Cash paid for acquired businesses	0	(206,447)
Liabilities assumed of acquired businesses	0	34,694
Non-cash additions to property, plant and equipment	783	1,938
Non-Cash Financing Activities:
Issuance of Company common stock upon vesting of restricted stock units	3,976	3,018
Dividends declared but unpaid	$ 2,444	$ 2,312