Goodwill and Other Intangible Assets (Summary Of Intangible Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 639,157	$ 615,996
Finite-Lived Intangible Assets, Accumulated Amortization	(201,815)	(150,228)
Finite-Lived Intangible Assets, Net	437,342	465,768
Indefinite-Lived Trademarks	19,900	20,041
Intangible Assets, Gross (Excluding Goodwill)	659,057	636,037
Total intangible assets	457,242	485,809
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	527,713	509,992
Finite-Lived Intangible Assets, Accumulated Amortization	(167,911)	(133,932)
Finite-Lived Intangible Assets, Net	$ 359,802	376,060
Customer Relationships [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	6 years
Customer Relationships [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	25 years
Advertiser Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 46,282	46,282
Finite-Lived Intangible Assets, Accumulated Amortization	(13,405)	(9,198)
Finite-Lived Intangible Assets, Net	$ 32,877	37,084
Finite-Lived Intangible Asset, Useful Life	11 years
Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 53,761	49,720
Finite-Lived Intangible Assets, Accumulated Amortization	(14,420)	(6,307)
Finite-Lived Intangible Assets, Net	$ 39,341	43,413
Finite-Lived Intangible Asset, Useful Life	20 years
Other Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 11,401	10,002
Finite-Lived Intangible Assets, Accumulated Amortization	(6,079)	(791)
Finite-Lived Intangible Assets, Net	$ 5,322	$ 9,211
Other Intangible Assets [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	2 years
Other Intangible Assets [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	15 years