Income Taxes (Components of Net Deferred Income Tax Asset and Liability) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Noncurrent deferred tax assets:
Net operating losses	$ 63,622	$ 65,257
Property, equipment and intangible basis differences	4,793	3,038
Accrued liabilities	9,659	11,933
Non-cash compensation	16,641	7,500
Deferred revenue	2,005	2,110
Allowance for doubtful accounts	5,691	5,978
Currency translation	56,604	34,895
Other	2,480	2,698
Valuation allowance	(50,628)	(38,802)
Total noncurrent deferred tax assets, net	110,867	94,607
Noncurrent deferred tax liabilities:
Property, equipment and intangible basis differences	(114,652)	(98,589)
Straight-line rents	(20,469)	(22,740)
Deferred foreign withholding taxes	(6,225)
Deferred lease costs	(2,192)	(2,242)
Other	(123)	(136)
Total noncurrent deferred tax liabilities, net	(32,794)	(29,100)
Other assets [Member]
Noncurrent deferred tax assets:
Total noncurrent deferred tax assets, net	18,330	1,670
Other Long-Term Liabilities [Member]
Noncurrent deferred tax liabilities:
Total noncurrent deferred tax liabilities, net	$ (51,124)	$ (30,770)