Divestiture (Details) € in Thousands, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2015 EUR (€)	Dec. 31, 2013 EUR (€)	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Jun. 30, 2015 USD ($)	Jul. 31, 2014 EUR (€)	Jul. 31, 2014 USD ($)	Jul. 31, 2013 EUR (€)	Jul. 31, 2013 USD ($)	Jul. 31, 2012 EUR (€)	Jul. 31, 2012 USD ($)
Disposal Group, Not Discontinued Operation, Disposal Disclosures [Abstract]
Date of divestiture	Jul. 31, 2012
Cash received as part of the selling price										€ 815	$ 1,014
Amount financed as part of selling price										5,351
Total selling price										€ 6,166
Total amount of installment payments received quarterly in 2013		€ 2,126	$ 2,826
Total amount of first anniversary payment received								€ 1,075	$ 1,435
Total amount of second anniversary payment received						€ 1,075	$ 1,418
Remaining amount of payments remaining to be received on the third anniversary date	€ 1,075				$ 1,198
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal | $				$ 784