Equity Method Investment (Details) $ in Thousands		12 Months Ended
	Oct. 31, 2009 USD ($) Royality_Installment_Payments	Dec. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 25, 2016 USD ($)	Sep. 23, 2014
Schedule of Equity Method Investments [Line Items]
Acquired interest in joint venture, Discovery Family Channel	50.00%				40.00%
Payment for purchase of interest in joint venture	$ 300,000
Percentage of fair market value of equity method investment		80.00%
Minimum royalty guarantee	$ 125,000
Number of annual installments for minimum royalty guarantee | Royality_Installment_Payments	5
Amount of annual installment for minimum royalty guarantee	$ 25,000
Discovery Communications, Inc. [Member]
Schedule of Equity Method Investments [Line Items]
Joint Venture - Ownership Interest					60.00%
Payments made to Discovery under tax sharing agreement		$ 7,087	$ 6,785	$ 6,520
Net (gains) losses related to change in value of joint venture option agreement		(540)	(4,790)	410
Discovery Communications, Inc. [Member] | Other Liabilities [Member]
Schedule of Equity Method Investments [Line Items]
Option Agreement		23,440	23,980
Liability associated with investment in joint venture, including imputed interest		$ 25,289	30,043
Discovery Family Channel [Member]
Schedule of Equity Method Investments [Line Items]
Acquired interest in joint venture, Discovery Family Channel		40.00%
Prepaid Royalties		$ 41,041	55,072
Interest in joint venture		236,934	237,996
Discovery Family Channel [Member] | Other Assets [Member]
Schedule of Equity Method Investments [Line Items]
Prepaid Royalties		27,825	39,114
Discovery Family Channel [Member] | Prepaid Expenses and Other Current Assets [Member]
Schedule of Equity Method Investments [Line Items]
Prepaid Royalties		13,216	15,958
Discovery Family Channel [Member] | Other Expense [Member]
Schedule of Equity Method Investments [Line Items]
Earnings (loss) of joint venture		21,145	$ 23,270	$ 23,764
Discovery Family Channel [Member] | Discovery Communications, Inc. [Member]
Schedule of Equity Method Investments [Line Items]
Gain from reduction of remaining present value of expected future payments, tax cuts and jobs act		$ 19,911