Balance Sheet Details (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Accounts receivable:
Accounts receivable	$ 80,850	$ 88,045
Allowance for doubtful accounts	5,703	5,307
Inventories:
Finished goods	139,888	129,091
Work in process	1,188	1,132
Raw materials	4,828	4,369
Repair parts	10,283	9,778
Operating supplies	1,362	1,489
Total inventories, less allowances of $4,091 and $4,808	157,549	145,859
Inventory allowances	4,091	4,808
Prepaid and other current assets:
Value added tax	3,850	1,834
Prepaid expenses	5,036	4,653
Deferred income taxes	4,070	3,074
Refundable and prepaid income taxes	0	3,107
Derivative asset	41	107
Total prepaid and other current assets	12,997	12,775
Other assets:
Deposits	936	733
Finance fees — net of amortization	13,539	9,427
Other assets	3,825	3,947
Total other assets	18,300	14,107
Accrued liabilities:
Accrued incentives	17,783	16,621
Workers compensation	7,128	8,484
Medical liabilities	3,537	3,607
Interest	3,732	13,008
Commissions payable	1,478	1,137
Contingency liability	2,719	2,719
Other accrued liabilities	6,486	8,351
Total accrued liabilities	42,863	53,927
Other long-term liabilities:
Deferred liability	5,591	4,070
Derivative liability	0	298
Other long-term liabilities	4,481	5,041
Total other long-term liabilities	10,072	9,409
Trade receivables [Member]
Accounts receivable:
Accounts receivable	79,624	86,523
Other receivables [Member]
Accounts receivable:
Accounts receivable	$ 1,226	$ 1,522