Income Taxes (Schedule Of Deferred Tax Assets And Deferred Tax Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Income Taxes [Abstract]
Accounts receivable	$ 123	$ 63
Accrued expenses and other current liabilities	145	114
Unearned revenue	436	209
Stock-based compensation	1,812	2,174
Other	411	36
Net operating loss carry forwards	13,814	2,602
Gross deferred tax assets	16,741	5,198
Valuation allowance	(15)	(167)
Net deferred tax assets	16,726	5,031
Intangible assets	29	68
Depreciation and amortization	56,478	40,015
Foreign deferred tax liabilities	2,664	2,953
Deferred subpart F income	5,790	5,193
Unrealized gain	(31)	39
Gross deferred tax liabilities	64,930	48,268
Net deferred tax liability	$ 48,204	$ 43,237