Fair Value of Financial Instruments, Significant Unobservable Inputs Roll Forward (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Apr. 01, 2018	Dec. 30, 2018
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of year	$ (23,440)	$ (23,980)
Gain from change in fair value	296	315
Balance at end of period	(23,144)	(23,665)
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Other income, net	8,100	8,592
Fair Value, Measurements, Recurring [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair Value of Available for Sale Investments, Fair Value Option	24,188	24,584	$ 23,913
Other income, net	$ 550	$ 448