Balance Sheet Details (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Accounts receivable:
Accounts receivable	$ 85,113	$ 94,379
Allowance for doubtful accounts	7,832	7,066
Inventories:
Finished goods	152,261	159,998
Work in process	1,625	1,183
Raw materials	4,432	4,944
Repair parts	10,558	10,763
Operating supplies	1,133	1,139
Total inventories, less loss provisions of $9,484 and $5,313	170,009	178,027
Inventory loss provision	9,484	5,313
Accrued liabilities:
Accrued incentives	19,771	21,450
Other accrued liabilities	22,036	23,729
Total accrued liabilities	41,807	45,179
Trade receivables
Accounts receivable:
Accounts receivable	82,851	91,324
Other receivables
Accounts receivable:
Accounts receivable	$ 2,262	$ 3,055