Inventories, net (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2015	Dec. 31, 2014
Inventories, net
Raw materials			$ 71,940	$ 65,723
Work in process			30,792	22,358
Finished goods (completed systems)			17,335	15,982
Inventories, net			120,067	104,063
Inventory reserves			$ 17,300	$ 23,600
Charges to cost of sales due to below normal production capacity	$ 600	$ 1,000