Intangible Assets and Goodwill (Details 1) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Summary of cost, accumulated amortization and net book value of intangible assets
Cost	$ 58,737	$ 55,039
Accumulated amortization	(51,116)	(46,780)
Customer relationships
Summary of cost, accumulated amortization and net book value of intangible assets
Cost	40,751	38,428
Accumulated amortization	(36,949)	(33,823)
Technology
Summary of cost, accumulated amortization and net book value of intangible assets
Cost	13,467	12,092
Accumulated amortization	(11,495)	(10,516)
License
Summary of cost, accumulated amortization and net book value of intangible assets
Cost	4,519	4,519
Accumulated amortization	$ (2,672)	$ (2,441)