Current report of foreign issuer pursuant to Rules 13a-16 and 15d-16 Amendments

Revenue Recognition (Narrative) (Details)

v3.8.0.1
Revenue Recognition (Narrative) (Details) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2018
Dec. 31, 2017
Deferred Revenue Arrangement [Line Items]    
Revenue recognized $ 19,200  
Deferred revenue noncurrent portion 15,139 $ 15,200
Increase in retained earnings effect on other non-current assets for the cumulative-effect adjustments 1,400  
Deferred sales commissions   $ 1,700
Next 12 Months [Member]    
Deferred Revenue Arrangement [Line Items]    
Revenue recognized 55,100  
Second Year [Member]    
Deferred Revenue Arrangement [Line Items]    
Revenue recognized 9,900  
There after [Member]    
Deferred Revenue Arrangement [Line Items]    
Revenue recognized $ 5,200