Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019
Cash flows from operating activities:
Net income	$ 99,497	$ 49,098
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	74,003	69,857
Loss on disposition of fixed assets	2,618	1,137
(Gain) on sale of marketable securities	0	(55)
Unrealized (gain) loss in value of equity securities	1,892	(1,637)
Deferred income taxes	3,247	1,483
Unrealized (gain) in SERP	(760)	(1,289)
Changes in operating assets and liabilities:
Inventories	13,816	17,519
Accounts receivable and prepaid expenses	(1,393)	7,205
Accounts payable and other liabilities	4,694	(9,153)
Income taxes	587	3,610
Other	(4,020)	972
Net cash provided by operating activities	194,181	138,747
Cash flows from investing activities:
Purchase of property and equipment	(83,574)	(70,084)
Proceeds from the sale of property and equipment	308	1,489
Purchase of marketable securities	(38,259)	(9,220)
Proceeds from the sale and maturities of marketable securities	3,690	5,325
Purchase of intangible assets	(127)	(558)
Change in SERP investment	(666)	(1,910)
Net cash used in investing activities	(118,628)	(74,958)
Cash flows from financing activities:
Dividends paid	(25,016)	(25,016)
Net cash used in financing activities	(25,016)	(25,016)
Net increase in cash and cash equivalents	50,537	38,773
Cash and cash equivalents at beginning of year	66,871	37,808
Cash and cash equivalents at end of period	$ 117,408	$ 76,581