Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jul. 01, 2017
Cash Flows from Operating Activities:
Net income	$ 64,985	$ 57,624
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation, amortization and accretion	13,004	10,192
Provision for doubtful accounts	(661)	150
Provision (benefit) for deferred income taxes	2,474	(2,666)
Provision for non-cash stock compensation	1,998	1,478
Changes in assets and liabilities:
Accounts receivable	(40,180)	(38)
Inventories	(6,122)	(29,690)
Prepaids and other current assets	(2,018)	(1,932)
Other assets	565	(2,503)
Accounts payable	17,816	18,158
Accrued compensation and other liabilities	(6,256)	(8,850)
Cash provided by operating activities	45,605	41,923
Cash Flows from Investing Activities:
Acquisition, net of cash acquired	(564)	(3,127)
Property, plant and equipment additions	(11,416)	(11,932)
Purchase of investments		(10,000)
Cash used in investing activities	(11,980)	(25,059)
Cash Flows from Financing Activities:
Contingent consideration	(2,037)
Other stock related activity	(318)	(1,043)
Purchase and cancellation of common stock	(28,066)	(35,734)
Cash used in financing activities	(30,421)	(36,777)
Effect of exchange rate changes on Cash and Cash Equivalents	(85)
Net Increase in Cash and Cash Equivalents	3,119	(19,913)
Cash and Cash Equivalents, Beginning of Period	71,691	149,121
Cash and Cash Equivalents, End of Period	74,810	129,208
Supplemental Cash Flow Information
Cash paid for interest expense	133	129
Cash paid for income taxes	$ 13,420	$ 38,679