Segment Information - Adjusted OIBDA by Segment and Reconciliation to Consolidated Net Income (Details) - USD ($) $ in Millions	3 Months Ended									12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018		Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Net income before allocation to non-controlling interests										$ 140.6	$ 107.9	$ 125.8
Provision for income taxes										10.9	4.9	4.1
Equity in earnings of investee companies, net of tax										(5.7)	(4.1)	(4.8)
Interest expense, net										134.9	125.7	116.9
Loss on extinguishment of debt										(28.5)	0.0	0.0
Other income (expense), net										(0.1)	0.4	(0.3)
Operating income (loss)	$ 98.0	$ 85.5	$ 88.7	$ 36.9	$ 91.3	$ 78.9	$ 32.9		$ 31.7	309.1	234.8	241.7
Restructuring charges										0.3	2.1	6.4
Net gain on dispositions	(0.8)	(1.9)	0.4	(1.5)	(1.3)	(1.3)	(2.7)		(0.2)	(3.8)	(5.5)	(14.3)
Impairment charge					0.0	0.0	42.9	[1]	0.0	0.0	42.9	0.0
Depreciation and amortization										194.5	185.0	189.8
Stock-based compensation	5.9	5.6	5.5	5.3	4.8	4.8	5.6		5.0	22.3	20.2	20.5
Adjusted OIBDA	151.7	140.3	143.6	86.8	143.8	129.3	125.2		81.2	522.4	479.5	444.1
Capital expenditures										89.9	82.3	70.8
U.S. Media
Segment Reporting Information [Line Items]
Operating income (loss)	115.8	103.1	101.9	55.5	102.4	96.0	93.8		50.6	376.3	342.8
Impairment charge											0.0
Adjusted OIBDA	158.6	147.3	145.8	94.6	143.9	136.2	131.2		88.9	546.3	500.2
Other
Segment Reporting Information [Line Items]
Operating income (loss)	2.8	(0.7)	3.3	(4.0)	3.9	(1.2)	(45.1)		(7.0)	1.4	(49.4)
Impairment charge											42.9
Adjusted OIBDA	7.8	4.3	8.8	1.2	9.7	4.2	4.2		(0.8)	22.1	17.3
Operating segments | U.S. Media
Segment Reporting Information [Line Items]
Operating income (loss)										376.3	342.8	320.6
Restructuring charges											0.9	2.3
Net gain on dispositions										(3.9)	(5.3)	(14.4)
Depreciation and amortization										173.9	161.8	169.6
Adjusted OIBDA										546.3	500.2	478.1
Capital expenditures										86.7	73.0	63.9
Operating segments | Other
Segment Reporting Information [Line Items]
Operating income (loss)										1.4	(49.4)	(16.0)
Restructuring charges											0.8	4.1
Net gain on dispositions										0.1	(0.2)	0.1
Depreciation and amortization										20.6	23.2	20.2
Adjusted OIBDA										22.1	17.3	8.4
Capital expenditures										3.2	9.3	6.9
Corporate
Segment Reporting Information [Line Items]
Operating income (loss)	(20.6)	(16.9)	(16.5)	(14.6)	(15.0)	(15.9)	(15.8)		(11.9)	(68.6)	(58.6)	(62.9)
Restructuring charges										0.3	0.4
Adjusted OIBDA	$ (14.7)	$ (11.3)	$ (11.0)	$ (9.0)	$ (9.8)	$ (11.1)	$ (10.2)		$ (6.9)	$ (46.0)	$ (38.0)	$ (42.4)

[1] As a result of an impairment analysis performed during the second quarter of 2018, we determined that the carrying value of our Canadian reporting unit exceeded its fair value and we recorded an impairment charge of $42.9 million on the Consolidated Statement of Operations. See Note 6. Goodwill and Other Intangible Assets: Goodwill to the Consolidated Financial Statements