Significant Customers & Concentration of Credit Risk (Details Textual) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Concentration Risk [Line Items]
Unbilled accounts receivable	$ 101,170		$ 107,673
Single Financial Services Customer
Concentration Risk [Line Items]
Unbilled accounts receivable	$ 29,400
Revenue | Single Customer
Concentration Risk [Line Items]
Concentration risk percentage	13.00%	15.00%
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	27.00%	22.00%
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	16.00%