Other General Expenses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Apr. 01, 2018
General and Administrative Expenses
Provision (credit) for uncollectible accounts and notes receivable	$ (50)	$ 1,539
General and administrative expenses	51,135	39,996
General and administrative expenses
General and Administrative Expenses
Starboard option valuation	5,552
Provision (credit) for uncollectible accounts and notes receivable	24	1,187
Loss on disposition of fixed assets	289	161
Other	(413)	969
Other general expenses	5,452	2,317
Special Committee costs	5,067
Administrative expenses	40,616	37,679
General and administrative expenses	51,135	$ 39,996
General and administrative expenses | Series B Preferred Stock
General and Administrative Expenses
Aggregate purchase price of shares	$ 50,000