Segment Information (Summary of Continuing Operations by Reportable Segment) (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended								12 Months Ended
	Jun. 30, 2020	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Revenues, net		$ 780,275	$ 654,015	$ 646,291	$ 734,375	$ 785,204	$ 718,597	$ 772,299	$ 784,221	$ 2,814,956	$ 3,060,321	$ 2,971,929
Operating income		$ 81,395	$ 139,477	$ 48,802	$ 172,970	$ 41,719	$ 168,438	$ 170,257	$ 244,863	442,644	625,277	726,909
Share-based compensation expense										52,908	64,133	60,979
Depreciation and amortization										104,606	101,098	91,281
Impairment charges	$ 25,100									122,227	106,603	4,486
Restructuring and other related charges										35,068	40,914	45,847
Cloud computing amortization										200
Majority-owned equity investees AOI										8,958	5,965	3,043
Adjusted operating income										766,611	943,990	932,545
Capital expenditures										46,595	91,604	89,802
Operating Segments [Member] | National Networks [Member]
Segment Reporting Information [Line Items]
Revenues, net										2,096,169	2,369,044	2,413,325
Operating income										656,425	804,422	825,770
Share-based compensation expense										42,536	52,977	48,621
Depreciation and amortization										40,539	32,674	33,728
Impairment charges										0	0	0
Restructuring and other related charges										20,553	13,453	17,160
Cloud computing amortization										0
Majority-owned equity investees AOI										0	0	0
Adjusted operating income										760,053	903,526	925,279
Capital expenditures										11,007	36,199	16,316
Operating Segments [Member] | International And Other [Member]
Segment Reporting Information [Line Items]
Revenues, net										746,527	734,143	598,306
Operating income										(224,228)	(170,039)	(93,326)
Share-based compensation expense										10,372	11,156	12,358
Depreciation and amortization										64,067	68,424	57,553
Impairment charges										122,227	106,603	4,486
Restructuring and other related charges										14,515	28,084	35,189
Cloud computing amortization										200
Majority-owned equity investees AOI										8,958	5,965	3,043
Adjusted operating income										(3,889)	50,193	19,303
Capital expenditures										35,588	55,405	73,486
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenues, net										(27,740)	(42,866)	(39,702)
Operating income										10,447	(9,106)	(5,535)
Share-based compensation expense										0	0	0
Depreciation and amortization										0	0	0
Impairment charges										0	0	0
Restructuring and other related charges										0	(623)	(6,502)
Cloud computing amortization										0
Majority-owned equity investees AOI										0	0	0
Adjusted operating income										10,447	(9,729)	(12,037)
Capital expenditures										0	0	0
Intersegment Eliminations [Member] | National Networks [Member]
Segment Reporting Information [Line Items]
Revenues, net										(22,617)	(32,762)	(33,600)
Intersegment Eliminations [Member] | International And Other [Member]
Segment Reporting Information [Line Items]
Revenues, net										(5,123)	(10,104)	(6,102)
Advertising [Member]
Segment Reporting Information [Line Items]
Revenues, net										875,816	993,833	1,036,079
Advertising [Member] | Operating Segments [Member] | National Networks [Member]
Segment Reporting Information [Line Items]
Revenues, net										802,332	904,253	944,675
Advertising [Member] | Operating Segments [Member] | International And Other [Member]
Segment Reporting Information [Line Items]
Revenues, net										74,338	89,659	91,404
Advertising [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenues, net										(854)	(79)	0
Distribution and Other [Member]
Segment Reporting Information [Line Items]
Revenues, net										1,939,140	2,066,488	1,935,850
Distribution and Other [Member] | Operating Segments [Member] | National Networks [Member]
Segment Reporting Information [Line Items]
Revenues, net										1,293,837	1,464,791	1,468,650
Distribution and Other [Member] | Operating Segments [Member] | International And Other [Member]
Segment Reporting Information [Line Items]
Revenues, net										672,189	644,484	506,902
Distribution and Other [Member] | Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenues, net										$ (26,886)	$ (42,787)	$ (39,702)