Income Taxes (Components Of Net Deferred Income Tax Asset And Liability) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Noncurrent deferred tax assets:
Net operating losses	$ 65,257	$ 50,143
Property, equipment and intangible basis differences	3,038	2,583
Accrued liabilities	11,933	12,264
Non-cash compensation	7,500	19,908
Deferred revenue	2,110	3,904
Allowance for doubtful accounts	5,978	6,187
Currency translation	34,895	33,088
Other	2,698	1,032
Valuation allowance	(38,802)	(70,233)
Total noncurrent deferred tax assets, net	94,607	58,876
Noncurrent deferred tax liabilities:
Property, equipment and intangible basis differences	(98,589)	(65,459)
Straight-line rents	(22,740)	(18,081)
Deferred lease costs	(2,242)	(1,087)
Other	(136)	(922)
Total noncurrent deferred tax liabilities, net	(29,100)	(26,673)
Other assets [Member]
Noncurrent deferred tax assets:
Total noncurrent deferred tax assets, net	1,670	774
Other Long-Term Liabilities [Member]
Noncurrent deferred tax liabilities:
Total noncurrent deferred tax liabilities, net	$ (30,770)	$ (27,447)