Significant Customers & Concentration of Credit Risk (Details Textual) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Concentration Risk [Line Items]
Unbilled accounts receivable		$ 96,460		$ 105,549
Single Customer
Concentration Risk [Line Items]
Unbilled accounts receivable		10,900
Single Financial Services Customer
Concentration Risk [Line Items]
Unbilled accounts receivable		$ 28,300
Revenue | Single Customer
Concentration Risk [Line Items]
Concentration risk percentage	13.00%	13.00%
Revenue | Single Financial Services Customer
Concentration Risk [Line Items]
Concentration risk percentage		14.00%	15.00%
Revenue | Automotive Industry
Concentration Risk [Line Items]
Concentration risk percentage		22.00%	22.00%
Revenue | Financial & Insurance Industry [Member]
Concentration Risk [Line Items]
Concentration risk percentage		20.00%	21.00%
Accounts Receivable | Single Customer
Concentration Risk [Line Items]
Concentration risk percentage		11.00%
Accounts Receivable | Single Financial Services Customer
Concentration Risk [Line Items]
Concentration risk percentage		19.00%