Description of Business and Summary of Significant Accounting Policies (Accounts Receivables and Allowances) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Document Period End Date			Jun. 30, 2017
Accounts receivable	$ 83,345		$ 83,345		$ 62,713
Allowance for doubtful accounts	3,356		3,356		$ 2,833
Deferred revenue included in accounts receivables	5,300		5,300
Provision for doubtful accounts	316	$ 698	723	$ 457
Allowance for Doubtful Accounts Receivable, Write-offs			313
Billed Revenues [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	61,600		61,600
Unbilled Revenues [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	$ 21,700		$ 21,700
Maximum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Delivery term for contractual elements of revenue arrangements			18 months