Commitments and Contingencies (Details) $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($)	Jun. 30, 2016 USD ($) item
Commitments and contingencies
Bank guarantees primarily for customer advances		$ 130.3
Revolving Loans
Commitments and contingencies
Bank guarantees primarily for customer advances	$ 137.7	$ 130.3
Korea
Commitments and contingencies
Sales to customers as a percentage of total revenue	2.00%
KFTC investigation
Commitments and contingencies
Number of bids under investigation | item		3