Other Income (Expense) (Details) - USD ($) $ in Thousands		1 Months Ended	3 Months Ended										12 Months Ended
		Jun. 30, 2018	Dec. 31, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 31, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Apr. 01, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Loss on early extinguishment of debt		$ 17,309	$ 723	$ 0	$ 0	$ 1,307	$ 9,274	$ 0	$ 17,309	$ 0			$ 2,030	$ 26,583	$ 0
Repurchase of convertible debentures													27,863	960,995	0
Schedule of Equity Method Investments [Line Items]
Foreign exchange gain (loss)													(1,414)	(1,991)	(4,536)
Interest income													8,445	11,940	6,482
Investment income (expense)	[1]												6,448	(1,646)	0
Other													61	(266)	(208)
Other Income (expense)													13,540	8,037	$ 1,738
Percentage of equity interest sold															50.00%
Loss on disposal of equity affiliate											$ (948)	$ 7,060	$ 0	$ 0	$ 6,112
Equity affiliate [Member]
Schedule of Equity Method Investments [Line Items]
Amounts reclassified out of AOCI, net of tax															$ 1,110
Convertible Senior Notes, Due 2025 [Member]
Debt Instrument [Line Items]
Cash coupon rate			2.25%				2.25%						2.25%	2.25%
Principal amount of the debentures			$ 600,000				$ 600,000						$ 600,000	$ 600,000
Convertible Senior Debentures [Member]
Debt Instrument [Line Items]
Loss on early extinguishment of debt														26,583
Repurchase of convertible debentures														960,995
Principal amount of repurchased debt			$ 19,366				$ 538,444						$ 19,366	$ 538,444

[1] Recognized in "Other" subsequent to the prospective adoption of ASU 2016-01 on January 1, 2018.  Previously recorded in accumulated other comprehensive income until realized.