Significant Customers & Concentration of Credit Risk (Details Textual) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Concentration Risk [Line Items]
Unbilled accounts receivable		$ 115,951		$ 107,673
Single Customer
Concentration Risk [Line Items]
Concentration risk percentage		11.00%
Unbilled accounts receivable		$ 12,300
Single Financial Services Customer
Concentration Risk [Line Items]
Unbilled accounts receivable		$ 17,500
Revenue | Single Customer
Concentration Risk [Line Items]
Concentration risk percentage	14.00%	13.00%
Revenue | Single Financial Services Customer
Concentration Risk [Line Items]
Concentration risk percentage		11.00%	14.00%
Revenue | Automotive Industry
Concentration Risk [Line Items]
Concentration risk percentage		28.00%	21.00%
Revenue | Financial & Insurance Industry [Member]
Concentration Risk [Line Items]
Concentration risk percentage		17.00%	20.00%
Accounts Receivable | Single Financial Services Customer
Concentration Risk [Line Items]
Concentration risk percentage		10.00%