Cash and Receivables Allowance for Doubtful Accounts Receivable (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 29, 2020	Mar. 31, 2019
Allowance for Doubtful Accounts
Balance at beginning of period; accounts receivable	$ 3,314	$ 4,940
Provision for doubtful accounts; accounts receivable	588	(570)
Uncollectible accounts written off, net of recoveries; accounts receivable	(21)	(123)
Balance at end of period; accounts receivable	3,881	4,247
Balance at beginning of period; notes receivable	6,705	2,000
Provision for doubtful accounts; notes receivable	(8)	594
Uncollectible accounts written off, net of recoveries; notes receivable	(1,192)	6
Balance at end of period; notes receivable	5,505	2,600
Balance at beginning of period; total	10,019	6,940
Provision for doubtful accounts; total	580	24
Uncollectible accounts written off, net of recoveries; total	(1,213)	(117)
Balance at end of period; total	$ 9,386	$ 6,847