Major Customers and Concentration of Credit Risk (Details)	12 Months Ended
	Dec. 31, 2016 item division	Dec. 31, 2015
Major customers and concentration of credit risk
Percentage of concentration risk (as a percent)	10.00%
Largest customer
Major customers and concentration of credit risk
Number of divisions | division	2
Credit concentration risk
Major customers and concentration of credit risk
Excess cash balance, number of high credit quality financial institution | item	1
Net sales | Customer concentration risk | Largest customer
Major customers and concentration of credit risk
Percentage of concentration risk (as a percent)	24.00%	27.00%
Net sales | Customer concentration risk | Division one of largest customer
Major customers and concentration of credit risk
Percentage of concentration risk (as a percent)	20.00%	18.00%
Net sales | Customer concentration risk | Division two of largest customer
Major customers and concentration of credit risk
Percentage of concentration risk (as a percent)	4.00%	9.00%
Accounts receivable | Largest customer
Major customers and concentration of credit risk
Percentage of concentration risk (as a percent)	14.00%	17.00%