Supplemental Information (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quantifying Misstatement in Current Year Financial Statements [Line Items]
Accrued media	$ 172,691,000		$ 172,691,000		$ 216,931,000
Asset Impairment Charges	18,839,000	$ 0	19,000,000	$ 0	8,599,000	$ 87,204,000	$ 5,471,000
Impairment of Right-Of-Use Asset			5,619,000
Goodwill	706,946,000		706,946,000		731,691,000	732,752,000
Indefinite-lived intangible assets acquired			$ 14,600
Finite-lived intangible assets, remaining amortization period			5 years
Income tax expense (benefit)	(7,923,000)	2,088,000	$ 5,577,000	2,835,000	10,316,000	29,615,000	(168,358,000)
Income (loss) before income taxes and equity in earnings of non-consolidated affiliates	$ (4,617,000)	$ 9,215,000	$ 10,677,000	$ 10,195,000	20,867,000	(88,669,000)	86,022,000
Effective tax rate (percent)	171600.00%	22700.00%	52200.00%	27800.00%
Revenues	$ 259,678,000	$ 362,130,000	$ 587,420,000	$ 690,921,000	1,415,803,000	1,475,088,000	1,513,779,000
Increase (Decrease) in Accounts Receivable			$ (88,039,000)	$ 21,570,000
Restatement Adjustment
Quantifying Misstatement in Current Year Financial Statements [Line Items]
Asset Impairment Charges					780,000	7,147,000	1,056,000
Goodwill					(8,983,000)	(8,203,000)
Income tax expense (benefit)					(217,000)	(1,988,000)	(294,000)
Income (loss) before income taxes and equity in earnings of non-consolidated affiliates					(780,000)	(8,262,000)	(1,056,000)
Increase (Decrease) in Deferred Income Tax Assets					217,000	1,988,000	294,000	$ 3,587,000
Revenues					0	(1,115,000)	0
Goodwill, Period Increase (Decrease)					(780,000)	(7,147,000)	(1,056,000)
Increase (Decrease) in Accounts Receivable						(1,115,000)
Increase (Decrease) in Deferred Income Taxes					$ 217,000	$ 1,988,000	$ 294,000	$ 3,587,000