Long-Term Debt (Details) $ / shares in Units, $ in Thousands	3 Months Ended
	Apr. 04, 2020 USD ($) $ / shares	Mar. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Debt Instruments [Abstract]
Credit facility	$ 54,000		$ 0
Deferred financing costs	(15,826)		(16,784)
Long-term debt	552,096		499,147
Less current portion	0		0
Long-term debt, less current portion	552,096		499,147
Interest expense [Abstract]
Contractual coupon interest	3,419	$ 3,523
Non-cash amortization of debt discount	3,637	3,490
Other Non-cash Interest Expense	454	438
Total interest expense related to the debentures	7,510	7,451
Purchase price of extinguished debt	19,926
Allocated liability component of repurchased debt	9,837
Allocated equity component of repurchased debt	10,089
Loss on extinguishment of debt, including the write-off of portion of unamortized debt issuance costs	(2,920)	(1,307)
Convertible Senior Notes, Due 2025 [Member]
Debt Instruments [Abstract]
Convertible debt	$ 512,745		509,128
Issuance date	Jun. 12, 2018
Debt maturity date	Jun. 15, 2025
Cash coupon rate	2.25%
Nonconvertible debt borrowing rate at issuance	5.50%
Effective conversion rate	31.8278
Effective conversion price (in dollars per share) | $ / shares	$ 31.42
130% of the conversion price (in dollars per share) | $ / shares	$ 40.85
Debt instrument percentage of conversion price	130.00%
Debt instrument percentage of sales price of common stock	98.00%
Maximum threshold of quarterly cash dividends per share of common stock for not adjusting conversion rate of convertible notes | $ / shares	$ 0.085
Liability and equity components of convertible debentures [Abstract]
Principal amount of debt	$ 600,000
Interest expense [Abstract]
Contractual coupon interest	3,375	3,375
Non-cash amortization of debt discount	3,617	3,426
Other Non-cash Interest Expense	454	454
Total interest expense related to the debentures	7,446	7,255
Convertible Senior Debentures, Due 2040 [Member]
Debt Instruments [Abstract]
Convertible debt	$ 127		126
Issuance date	Nov. 09, 2010
Debt maturity date	Nov. 15, 2040
Cash coupon rate	2.25%
Nonconvertible debt borrowing rate at issuance	8.00%
Effective conversion rate	80.4668
Effective conversion price (in dollars per share) | $ / shares	$ 12.43
130% of the conversion price (in dollars per share) | $ / shares	$ 16.16
Convertible senior debentures call date	Nov. 20, 2020
Conversion period before maturity date	3 months
Debt instrument percentage of conversion price	130.00%
Debt instrument percentage of sales price of common stock	98.00%
Liability and equity components of convertible debentures [Abstract]
Principal amount of debt	$ 300
Convertible Senior Debentures, Due 2041 [Member]
Debt Instruments [Abstract]
Convertible debt	$ 1,050		6,677
Issuance date	May 13, 2011
Debt maturity date	May 15, 2041
Cash coupon rate	2.25%
Nonconvertible debt borrowing rate at issuance	8.375%
Effective conversion rate	58.7205
Effective conversion price (in dollars per share) | $ / shares	$ 17.03
130% of the conversion price (in dollars per share) | $ / shares	$ 22.14
Convertible senior debentures call date	May 20, 2021
Conversion period before maturity date	3 months
Debt instrument percentage of conversion price	130.00%
Debt instrument percentage of sales price of common stock	98.00%
Liability and equity components of convertible debentures [Abstract]
Principal amount of debt	$ 2,640
Interest expense [Abstract]
Principal amount of repurchased debt	14,250
Net carrying value of repurchased debt	5,645
Convertible Senior Debentures [Member]
Interest expense [Abstract]
Contractual coupon interest	44	148
Non-cash amortization of debt discount	20	64
Other Non-cash Interest Expense	0	(16)
Total interest expense related to the debentures	64	$ 196
Convertible Debt [Member]
Liability and equity components of convertible debentures [Abstract]
Principal amount of debt	602,940		617,190
Unamortized discount	(89,018)		(101,259)
Carrying value of liability component	513,922		515,931
Equity component - net carrying value	86,478		92,391
Convertible Debt [Member] | Convertible Senior Notes, Due 2025 [Member]
Liability and equity components of convertible debentures [Abstract]
Principal amount of debt	600,000		600,000
Unamortized discount	(87,255)		(90,872)
Carrying value of liability component	512,745		509,128
Equity component - net carrying value	85,262		85,262
Convertible Debt [Member] | Convertible Senior Debentures [Member]
Liability and equity components of convertible debentures [Abstract]
Principal amount of debt	2,940		17,190
Unamortized discount	(1,763)		(10,387)
Carrying value of liability component	1,177		6,803
Equity component - net carrying value	$ 1,216		$ 7,129