Significant Customers & Concentration of Credit Risk (Details Textual) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Concentration Risk [Line Items]
Unbilled accounts receivable		$ 119,008		$ 107,673
Single Customer
Concentration Risk [Line Items]
Concentration risk percentage		13.00%
Unbilled accounts receivable		$ 15,500
Single Financial Services Customer
Concentration Risk [Line Items]
Unbilled accounts receivable		$ 23,800
Revenue | Single Customer
Concentration Risk [Line Items]
Concentration risk percentage	15.00%	14.00%
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		29.00%	23.00%
Revenue | Financial & Insurance Industry [Member]
Concentration Risk [Line Items]
Concentration risk percentage		15.00%	20.00%
Accounts Receivable | Single Financial Services Customer
Concentration Risk [Line Items]
Concentration risk percentage		12.00%