SCHEDULE II-VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
SEC Schedule, 12-09, Allowance, Credit Loss [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	$ 836	$ 980	$ 637
Charged to costs and expenses	(81)	(286)	422
Other additions	263	220	(61)
Deductions	248	78	18
Balance at end of year	770	836	980
Balance of valuation allowance	770	980	980
Environmental Reserves [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	23,619	28,004	21,864
Charged to costs and expenses	1,659	1,981	7,491
Other additions	0	0	0
Deductions	4,412	6,366	1,351
Balance at end of year	20,866	23,619	28,004
Balance of valuation allowance	20,866	28,004	21,864
SEC Schedule, 12-09, Valuation Allowance, Deferred Tax Asset [Member]
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	25,311	30,316	18,681
Charged to costs and expenses	2,919	1,209	7
Other additions	290	150	11,628
Deductions	5,390	6,364	0
Balance at end of year	23,130	25,311	30,316
Period increase in valuation allowance			11,600
Balance of valuation allowance	$ 23,130	$ 30,316	$ 18,681