Business Segment, Geographic and Major Customer Information - Major Customers (Details) - Customer Concentration Risk - Sales	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Customer A
Segment Reporting Information [Line Items]
Percentage of revenue by major customers	13.30%	17.50%	12.70%	20.70%
Customer B
Segment Reporting Information [Line Items]
Percentage of revenue by major customers	10.10%	13.30%	9.90%	12.80%