Income Taxes (Schedule Of Deferred Tax Assets And Deferred Tax Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Income Taxes [Abstract]
Accounts receivable	$ 307	$ 123
Accrued expenses and other current liabilities	423	145
Unearned revenue	856	436
Stock-based compensation	2,280	1,812
Other	616	442
Net operating loss carry forwards	27,225	13,814
Gross deferred tax assets	31,707	16,772
Valuation allowance		(15)
Net deferred tax assets	31,707	16,757
Intangible assets	2,946	29
Depreciation and amortization	73,305	56,478
Foreign deferred tax liabilities	760	2,664
Deferred subpart F income	6,500	5,790
Gross deferred tax liabilities	83,511	64,961
Net deferred tax liability	$ 51,804	$ 48,204