Divestiture (Details) € in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2013 EUR (€)	Dec. 31, 2013 USD ($)	Dec. 31, 2012 EUR (€)	Dec. 31, 2012 USD ($)	Jul. 31, 2015 EUR (€)	Jul. 31, 2015 USD ($)	Jul. 31, 2014 EUR (€)	Jul. 31, 2014 USD ($)	Jul. 31, 2013 EUR (€)	Jul. 31, 2013 USD ($)	Jul. 31, 2012 EUR (€)
Disposal Group, Not Discontinued Operation, Disposal Disclosures [Abstract]
Date of divestiture	Jul. 31, 2012
Proceeds from divestiture				€ 815	$ 1,014
Amount financed as part of selling price												€ 5,351
Total selling price												€ 6,166
Amount of installment payments received quarterly 2013		€ 2,126	$ 2,826
First anniversary payment received										€ 1,075	$ 1,435
Second anniversary payment received								€ 1,075	$ 1,418
Third and final anniversary payment received						€ 1,075	$ 1,185
Disposal Group, Including Discontinued Operation, Operating Income (Loss) | $					$ 784