Summary Of Significant Accounting Policies (Narrative) (Details) - USD ($) shares in Thousands, $ in Thousands		3 Months Ended	12 Months Ended
	Nov. 25, 2014	Sep. 30, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Summary of Significant Accounting Policies [Line Items]
Gain on sale of investments			$ 38,326	$ 12,461
Cost-method investments, carrying value			8,800	49,600
Cost-method investments, impairment loss			0	0	$ 0
Interest cost capitalized			800	300	100
Deferred lease costs			10,900	12,400	12,800
Amortization expense			9,000	6,800	5,500
Unamortized deferred lease costs			$ 30,600	28,500
Intangible assets, useful life			15 years
Impairment charge recognized, related to long-lived assets		$ 56,700	$ 94,800	23,800	29,000
Write-offs relating to long-lived assets and intangibles			$ 31,600	$ 18,400	$ 23,500
Stock options outstanding			3,794
Restricted stock outstanding			277	295
Business acquistions period after closing date to determine additional adjustments			1 year
Acquired intangible assets, useful life			15 years
Intercompany Loan Maxiumum Amount	$ 750,000
Intercompany Foreign Currency Balance, Amount	$ 455,800
Loss on remeasurement of U.S. denominated intercompany loan			$ (178,854)	$ (22,965)
Privately Held Company [Member]
Summary of Significant Accounting Policies [Line Items]
Proceeds from sale of other investments			89,700	20,900
Gain on sale of investments			$ 38,300	$ 12,500
Minimum [Member]
Summary of Significant Accounting Policies [Line Items]
Lease term			5 years
Duration of site development projects			3 months
Business acquisitions performance target period			1 year
Maximum [Member]
Summary of Significant Accounting Policies [Line Items]
Lease term			10 years
Duration of site development projects			12 months
Business acquisitions performance target period			3 years