Description of Business and Summary of Significant Accounting Policies (Accounts Receivables and Allowances) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	$ 102,813		$ 102,813		$ 62,713
Allowance for doubtful accounts	3,560		3,560		$ 2,833
Deferred revenue included in accounts receivables	4,900		4,900
Provision for doubtful accounts	385	$ 243	1,107	$ 700
Allowance for Doubtful Accounts Receivable, Write-offs			513
Billed Revenues [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	76,700		76,700
Unbilled Revenues [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable	$ 26,100		$ 26,100
Maximum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Delivery term for contractual elements of revenue arrangements			18 months